Creative Destruction

April 15, 2006

Experts answer: What Does DNA Evidence Prove?

Filed under: Current Events,Feminist Issues — Ampersand @ 2:22 am

(Note: I did the research and the writing for this post before Blac(k)ademic posted her critique of writing which treats rape “like a damn sports event where we are taking sides and rooting for each side based on DNA samples.” I’ll don’t really disagree with Blac(k)ademic, but I still think that engaging with the particulars is sometimes necessary, and is possible to do without treating rape like a sports event. I intend to post more on this later, but for now I gotta get away from the computer for a while.)

Now that DNA evidence has not shown a connection between Mary Doe, the alleged victim, and any of the Duke Lacrosse players, many people are saying that the case should be closed. Some are even saying that the DNA proves that no rape happened, and Mary Doe made a false accusation.

To tell you the truth, until I began researching this post, I knew nothing about DNA evidence beyond what I’ve seen on TV detective shows. The public comments about DNA in this case have all come from defense lawyers, whose statements may be more about what they want potential jurors to hear than about what the most truthful analysis is. (The same is true for public statements made by the DA, of course).

In a comment at Ginmar’s livejournal, Fiona64 identified herself as a “forensic science geek” who, while not an expert, at least knows more about DNA evidence than the average CSI watcher. I emailed her with a bunch of questions, which she was kind enough to answer.

That gave me the idea of emailing evidence analysts – experts who write technical papers and testify in courtrooms – and asking them background questions. I cut down my list of questions to just four (I thought there was a better chance of getting responses if there were fewer questions asked) and emailed several DNA evidence experts. To my surprise, several were kind enough to email me back.

So here I’m going to summarize the answers. Then, at the bottom of the post, you’ll find the full text of all the responses I got, along with a brief description of each expert’s background (the background descriptions are quoted from this website). I’ve tried to be honest in how I’ve quoted folks, but I’ve also been fitting in writing this post around Passover and work, so my advice is to go ahead and read the full answers.

Keep in mind that these answers are only general background comments about what DNA evidence can and cannot prove, not specific comments about the Duke rape case.

On the whole, the most striking thing to me about the responses is the lack of unanimity between the experts. It’s pretty clear that DNA evidence is a field in which experts can, and do, disagree.

Question one: 1. If DNA evidence fails to prove that an accused person raped an alleged rape victim, does that prove that the accused person could not have raped the alleged victim?

Here, all experts agreed that it is possible for DNA to not be left behind by a rapist, but different experts seemed to disagree about how likely that is.

Jennifer Friedman, of the Los Angeles County Innocence Project, gave an answer which implied that it’s extremely unlikely that anyone could rape and not leave DNA behind (unless they used a condom). “In general, if there is a sexual assault with penetration either vaginal or anal and no condom is used one would expect DNA to be present. Even if the perpetrator did not ejaculate, his epithelial cells will often times be left behind. In order to answer this question most accurately, I would need to know specifically what is alleged to have occurred. Occasionally, DNA may be left on the alleged victim and yet the person who swabbed the area may have missed the area with the DNA, but this is rare.”

On the other hand, Elizabeth Johnson flatly answered “no” (perhaps because she was in a rush), and William Thompson wrote that “absense of evidence is not necessarily evidence of absense.”

2. Is it possible for a rape to happen and for no useful DNA evidence to be left behind? Put another way, if someone says she was raped, but no DNA evidence supports her claim, does that prove she made a false rape report?

Not one expert was willing to say that absense of DNA evidence is proof of a false rape accusation. But how strongly they said “no” to this question varied significantly.

On the “weak no” side, Dan Krane wrote: “It is worth noting that DNA tests are amazingly sensitive (DNA profiles can be generated from as little material as that left behind in a fingerprint) and Y-STR tests have the potential of determining a male’s DNA profile even when a female’s DNA is present in hundreds or thousands of times greater quantities. Scientists are always wary of asserting that the absence of evidence is not proof of absence but it certainly is reasonable to expect to find a rapist’s DNA associated with a victim when the victim presents herself to investigators within hours of an attack and when she has not bathed, the rapist did not use a condom and ejaculation occurred.”

On the other hand, Simon Ford believes that CSI has given the public an inflated idea of how certain and quick DNA tests are, and writes “If the claim is such that one would expect to see biological material and none is found, then sure it may be an indication of a false claim, but there are really so many other potential explanations, particularly when just dealing with the first round of DNA testing, such as issues like condom use, vasectomy, choice of test (autosomal STR v. Y-STR), choice of samples to test, many other things like this can all play a part.”

And William Shields wrote “unless the victim stated that she was sure there no condoms used the absence of DNA could not prove she was mistaken much less that she made a false report.”

Finally, Fiona64 writes “It may, however, mean that the proverbial net needs to be thrown wider in order to obtain a different pool of suspects.”

3. I’ve seen it claimed that mixed DNA from multiple rapists will not necessarily match the individual DNA of any of the rapists, so multiple rapists not using condoms may be unidentifiable. This seems dubious to me. Do you know if this is true?

The answers given by experts to this question were truly all over the place. Several experts do not think there is any danger of a false exclusion in such a scenario. For instance, William Thompson of the University of California wrote “It depends on the way the analyst chooses to interpret the mixed profile. In the cases I look at, the analyst are usually quite lenient about what they will call a ‘match.’ A mixture of DNA from three or more men can often be interpreted in a manner that allows a very substantial fraction of the male population to be ‘included’ as a potential contributor.”

Another expert, Jennifer Friedman, writes “If someone is excluded, he is definitively excluded.”

But William Shields of the State University of New York wrote, “If three, four, or more people donate DNA then there will be so many alleles in a mixture that very few if any people can be excluded as potential contributors. In such an event the evidence does become useless.”

4. Is it possible for a condom to be used, without physical evidence of condom use (traces of latex, etc) being left behind?

A few experts I contacted didn’t feel they knew enough to answer this question.

Of the experts who answered this question, however, all agreed that condoms could be used and not necessarily detected. Elizabeth Johnson wrote, “Testing for these substances is not typically done, despite what you see on CSI. There has been some research done re spermicides on condoms, but none of this is done as part of a typical test and validated methods for casework aren’t there yet.” William Shields wrote “This question is better asked of a forensic chemist but I do know that such traces are often but not always left behind.” And William Thompson flatly answered “yes.”

So what do I conclude from all this?

Despite the DNA evidence, from what the experts say it’s possible that condoms were used, preventing DNA evidence from being left behind. It’s also possible that the rapists were party guests but not members of the lacrosse team. The idea that this case has now been settled, or that Mary Doe has been proven a liar, rests on weak and inconclusive evidence. It is clear that those who have say the DNA evidence proves no rape took place are vastly exaggerating what DNA evidence (or the lack of DNA evidence) can conclusively show.

(The other evidence I’ve seen put forward to support the “it was a false rape accusation” arguments – 911 calls, photos, Mary Doe’s past arrest, etc. – I don’t see as even a tiny bit persuasive, for reasons I’ll describe in an upcoming post.)

I don’t deny that it’s possible no rape took place, and clearly this possibility is supported (but far from proven) by initial DNA results. Still, given all the evidence available so far, I continue to believe Mary Doe’s claim that she was raped at the lacrosse player’s party. And although there may not be enough evidence for “guilty beyond a reasonable doubt,” that in and of itself doesn’t prove that no rape took place. Rape is, contrary to popular belief, an extremely difficult crime to prove in a courtroom; there are many more rapists than there are tried and convicted rapists.

* * *

Below are the full answers given by each of the experts. I think all the answers are pretty interesting, and recommend reading them all. If you only have time for one, though, I think Simon Ford’s email is especially valuable both for the background information it contains and for the picture it paints of how complex questions of DNA evidence can be.

Fiona64

I will do my best to answer your questions, with the caveat that I am *not* an evidence analyst; I work for the lab and am majoring in forensic anthropology (I will eventuallly work *in* the lab). I can find source material to answer the things about which I’m uncertain, though, so please feel free to ask away.

If DNA evidence fails to prove that an accused person raped an alleged rape victim, does that prove that the accused person could not have raped the alleged victim?

Nope. Lack of DNA evidence is not automatically exculpatory. Really, the vast majority of crimes do not have DNA evidence.

Is it possible for a rape to happen and for no useful DNA evidence to be left behind?

Most assuredly. I can think of a number of scenarios in which that might be the case; the obvious one is when a rapist uses a condom.

Is it possible for no conclusive DNA evidence to be left behind even if the rapist(s) doesn’t use a condom?

This is a little trickier; rape with an object, or by an assailant who shaves his body hair, or in a “drug-assisted” situation (i.e., GHB, Rohypnol) are just a couple of scenarios in which this might be the case.

Other circumstances in which rape may have occurred without DNA being present in the victim include the assailant having had a vasectomy, failed to ejaculate, or is azoospermic (a shmancy word that means his semen does not contain spermatazoa).

If DNA evidence fails to prove a connection between a group of suspects and an alleged rape victim, does that prove that no rape took place?

Not at all. It may, however, mean that the proverbial net needs to be thrown wider in order to obtain a different pool of suspects.

You’ve said that “Mitochondrial DNA (from hair samples) and epithelial DNA (from shed skin cells on clothing, for example) takes significantly longer to process. We have come along way with DNA analysis; a sperm sample used to take 3 months to analyze, and we can now do it in 48 hours. However, mitochondrial and epithelial samples still take as much as 3 weeks just to replicate an adequate sample to test.”

Can you explain the significance of this? Is it possible for the mitochondrial and epithelial DNA to have different results than the initial DNA analysis?

Nuclear DNA is what most people think of when it comes to evidence — that’s what comes from blood, semen, pulled hair (with root bulb, which is where the nuclear DNA is) and buccal (cheek) cells. Mitochondrial DNA can come from bones, teeth or cut hair … and it has to be replicated by PCR (polymerase chain reaction) most of the time in order to have an adequate sample to look at. The difference comes in with mDNA in that it is matriarchal in nature; that is, your mDNA is virtually identical to your mother’s, grandmother’s, etc. Without a matriarchal sample for comparison, mDNA is not particularly useful. Furthermore, if two potential assailants are siblings, their mDNA will be nearly identical. :-/ BTW, the reason that mDNA could be used to identify the corpse of Laci Peterson (which is how they did it) was that they had bone samples *and* the availability of Laci Peterson’s mom for additional samples.

Epithelial cells can only be tested for DNA if they contain glycogen … and not all epithelials do.

So, as you can see, it’s not always a straightforward thing. Ideally, all cases would be awash with nuclear DNA … from a forensic point of view, anyway. It would make it very easy to get the right person every single time, and it’s just not like that.

I’ve seen it claimed that mixed DNA from multiple rapists will not necessarily match the individual DNA of any of the rapists, so multiple rapists not using condoms may be unidentifiable. Do you know if this is true?

I don’t know whether it’s true, but it stands to reason strictly from a physical science perspective. You have liquid (semen) from more than one source, and it’s going to have pretty much the same density. An analyst could say “there’s more than one source here,” but not be able to tease out which cells go with which source. It’s like pouring a bottle of Aquafina and a bottle of Dasani into the same pitcher; you know it’s two different kinds of water, from two different sources, but you can no longer tell once they’ve intermingled which one is which.

Is it possible for a condom to be used, without physical evidence of condom use (traces of latex, etc) being left behind?

Again, I don’t know the exact answer here. The theory is that anything you touch could potential transfer trace evidence; the best test I’ve ever seen for this is suggesting that one walk in stocking feet from one room to the next, and then see what you took with you. However, I could envision a scenario in which non-latex (lambskin) condoms might have been used … and those typically also do not have spermicide.

Jennifer Friedman
Jennifer Friedman, J.D., Deputy Public Defender and Forensic Science Coordinator with the Los Angeles Public Defender’s Office. She has litigated several high-profile cases where DNA testing played a pivotal role and is also the founder and former head of the Los Angeles County Innocence Project.

1. If DNA evidence fails to prove that an accused person raped an alleged rape victim, does that prove that the accused person could not have raped the alleged victim?

It does not absolutely prove that the accused could not have committed the crime. However, in general, if there is a sexual assault with penetration either vaginal or anal and no condom is used one would expect DNA to be present. Even if the perpetrator did not ejaculate, his epithelial cells will often times be left behind. In order to answer this question most accurately, I would need to know specifically what is alleged to have occurred. Occasionally, DNA may be left on the alleged victim and yet the person who swabbed the area may have missed the area with the DNA, but this is rare.

2. Is it possible for a rape to happen and for no useful DNA evidence to be left behind? Put another way, if someone says she was raped, but no DNA evidence supports her claim, does that prove she made a false rape report?

See above.

3. I’ve seen it claimed that mixed DNA from multiple rapists will not necessarily match the individual DNA of any of the rapists, so multiple rapists not using condoms may be unidentifiable. This seems dubious to me. Do you know if this is true?

I would disagree with this. If DNA is left behind, particularly in an intimate sample (so that the male and female DNA may be separated)even if there is a mixture, individuals will either be included or excluded based on the alleles present. If someone is excluded, he is definitively excluded. If someone is included, this might be significant or insignificant depending upon how many others are also included. What is difficult about mixtures, is determining which genetic profiles are actually present. Thus, if someone is excluded, he is excluded. But if someone is included, he may not necessarily be the person who left the DNA.

4. Is it possible for a condom to be used, without physical evidence of condom use (traces of latex, etc) being left behind?

This is not my area of expertise but I have seen a number of cases where the lab tests for the presence of spermicide and concludes based on its present that a condom was recently used.

Simon Ford
Trained primarily in molecular biology and biochemistry, Dr. Ford is the Founder and President of Lexigen Science and Law Consultants, a firm that specializes in providing advice to lawyers about genetic evidence since 1988. He has personally reviewed the DNA evidence from thousands of criminal investigations and has conducted numerous workshops for agencies on the analysis of STR test results.

Barry:

For your information, I’ve not been following the reports of the Duke rape case allegations, all I know is that the incident allegedly involves multiple potential assailants, and that the initial DNA report failed to establish a link with any of the individuals tested from the Duke team — that’s about all I know.

One important issue underlying the media coverage of a story like the Duke incident is that TV shows like CSI have raised unrealistic expectations in the general public of what forensic science, and specifically DNA testing, can do. People get the idea that you run a test, it takes just a few hours, and you get a definitive answer yes or no. In truth DNA testing takes much longer, can produce ambiguous results and has always got to be considered in the framework of the specific question asked and in the context of other biological tests, such as microscopic observation of cell types (for example sperm in a rape case) or serological tests for body fluids (such as semen). Also there are different types of DNA tests. Many labs start with the standard autosomal STR test on sex assault cases. This test looks at regions of DNA which differ from person-to-person and are scattered across the non-sex chromosomes. In some instances, for example samples which contains large amounts of (female) victim DNA, the assailant’s DNA may get swamped out, and so the lab can use one of the Y-STR tests, which homes in on variable regions only found on the Y-chromosome (which men have and women do not). In cases of this type, the initial (autosomal) STR DNA report may fail to report a match with the suspect but a later Y-STR DNA report may incriminate. There can also be other simpler explanations for a negative initial report being followed by a later incriminating report, such as refining the choice of samples to test. I would not read too much into a negative report until the whole testing scenario has been completed.

With regard to your specific questions. I don’t know much about testing for latex and detection of condom use. The question regarding mixtures is easiest to deal with. A mixed DNA profile will consist of the DNA profiles of the contributing individuals superimposed, one on top of another. It can be quite complex, because not all contributions are going to be in equal amounts, causing unevenness in the profile, and the DNA profiles of the individuals who contribute least to the mixture may well drop below detectable levels. So the first potential problem is that minor contributors may be missed. Beyond that though, it is still possible to answer the question as to whether a specific profile can be excluded as being a potential contributor to the mixed profile.

Once you have determined that a particular profile cannot be excluded the problem is how to express the significance of that observation; and this is were statistics comes in. The statistical calculations for mixture cases can be quite complicated. In single source cases labs often report stats in the trillions and quadrillions but in mixture cases the stats can be dramatically eroded — the more contributors, the less powerful the stats — it is not uncommon to see stats in the tens or hundreds in mixture cases. The presence of multiple contributors can erode the statistical power of the test to the point whereby, if there are enough contributors, the test really doesn’t have any useful meaning any more. All the lab would be able to say is that there were a large number of contributors, but no further conclusions could be drawn.

Your two remaining questions are more difficult to answer, because they deal with DNA evidence without giving the context of the specific question being asked for that case or information about other biological testing. Every case is different and has its own nuances. With regard to DNA it all hinges on whether the specific allegations claimed by the victim are amenable to being proven right or wrong by DNA. If the claim is such that one would expect to see biological material and none is found, then sure it may be an indication of a false claim, but there are really so many other potential explanations, particularly when just dealing with the first round of DNA testing, such as issues like condom use, vasectomy, choice of test (autosomal STR v. Y-STR), choice of samples to test, many other things like this can all play a part.

Sorry I can’t be more definitive, but I hope these comments help illustrate the difficult challenges that labs and attorneys face with regard to the real world usage of DNA evidence in criminal cases.

All the best,

Simon Ford

Elizabeth Johnson
Elizabeth Johnson, Ph.D. has been a practicing forensic scientist for the past thirteen years, specializing in forensic biology and DNA issues. Dr. Johnson established and directed the DNA laboratory at the Harris County Medical Examiner’s Office in Houston, Texas from 1992-1996. She then worked at Technical Associates, a private criminalistics laboratory in Ventura, California, for six years. After leaving Technical Associates, Dr. Johnson has gone into solo practice, based in Thousand Oaks, California, providing testing, review, consultation, testimony, and education to those in need of assistance with forensic DNA.

Barry,

Sorry for the brevity of the answers…must scram for court.

Elizabeth Johnson

1. If DNA evidence fails to prove that an accused person raped an alleged rape victim, does that prove that the accused person could not have raped the alleged victim?

No

2. Is it possible for a rape to happen and for no useful DNA evidence to be left behind? Put another way, if someone says she was raped, but no DNA evidence supports her claim, does that prove she made a false rape report?

It is possible that penetration occurs w/o ejaculation therefore not leaving sufficient biological material in her to be detected in typical DNA tests.

3. I’ve seen it claimed that mixed DNA from multiple rapists will not necessarily match the individual DNA of any of the rapists, so multiple rapists not using condoms may be unidentifiable. This seems dubious to me. Do you know if this is true?

You cannot identify an individual from a mixture. You can exclude or fail to exclude a person from a mixture. Still very useful information.

4. Is it possible for a condom to be used, without physical evidence of condom use (traces of latex, etc) being left behind?

Testing for these substances is not typically done, despite what you see on CSI. There has been some research done re spermicides on condoms, but none of this is done as part of a typical test and validated methods for casework aren’t there yet.

Dan Krane
Dan Krane, Ph.D., Associate Professor of Biological Sciences at Wright State University, his research lab generates thousands of DNA profiles each year as well as the lead author of the best selling undergraduate textbook on bioinformatics. A leading authority on forensic DNA evidence, he is founder and CEO of Forensic Bioinformatics, Inc. and has testified as an expert witness in approximately fifty cases.

1. If DNA evidence fails to prove that an accused person raped an alleged rape victim, does that prove that the accused person could not have raped the alleged victim?

There is no “pat answer” to your question. The circumstances of the investigation (particularly the victim’s recounting of the events when it is available) almost always need to be taken into consideration. For instance, consider a situation in which a woman asserts that she was raped by a single individual and that she had not had sexual contact with any other individual for many days. If investigators identify a suspect and then find that his DNA profile is not the same as the source of semen from the victim, then those test results can be construed as proof that the suspect was not the perpetrator.

2. Is it possible for a rape to happen and for no useful DNA evidence to be left behind? Put another way, if someone says she was raped, but no DNA evidence supports her claim, does that prove she made a false rape report?

It is possible for no DNA profile to be generated during a rape investigation even though a rape had occurred. The greater the amount of time between the rape and evidence collection, the greater the likelihood that no DNA will be recovered. Other factors such as: did the victim bathe or not, did the rapist use a condom or not, and did the rapist ejaculate or not also need to be considered. However, it is worth noting that DNA tests are amazingly sensitive (DNA profiles can be generated from as little material as that left behind in a fingerprint) and Y-STR tests have the potential of determining a male’s DNA profile even when a female’s DNA is present in hundreds or thousands of times greater quantities. Scientists are always wary of asserting that the absence of evidence is not proof of absence but it certainly is reasonable to expect to find a rapist’s DNA associated with a victim when the victim presents herself to investigators within hours of an attack and when she has not bathed, the rapist did not use a condom and ejaculation occurred.

3. I’ve seen it claimed that mixed DNA from multiple rapists will not necessarily match the individual DNA of any of the rapists, so multiple rapists not using condoms may be unidentifiable. This seems dubious to me. Do you know if this is true?

Mixed DNA samples are generally much more difficult to interpret than unmixed samples are. The statistics associated with mixtures are typically much less impressive than those associated with unmixed samples as a direct result. It is possible for large amounts of one or two people’s DNA relative to other contributors to a mixture to mask or obscure the presence of DNA from secondary contributors. However, the presence of one person’s DNA will not change the DNA profile of another contributor to a sample.

4. Is it possible for a condom to be used, without physical evidence of condom use (traces of latex, etc) being left behind?

I don’t think that my opinion on this would be any more expert than your own so I’ll let you come to your own conclusion!

William Shields
Dr. Shields is a Professor of Biology at the State University of New York, Syracuse. Dr. Shields has become one of the most easily recognized experts in the field of DNA profiling through his participation as a testifying expert in countless highly publicized trials including the on-going CA v. Peterson. He has published widely in the areas of population genetics and mitochondrial DNA testing.

Dear Barry: It doesn’t take long to answer your questions so here goes:

1. If DNA evidence fails to prove that an accused person raped an alleged rape victim, does that prove that the accused person could not have raped the alleged victim?

It depends. If condoms were used then the rapist might not leave DNA evidence during the commission of the crime. If the victim said no condoms were used then no DNA would be evidence that she might be lying. If DNA was found but did not match the accused this would be evidence that the accused did not leave the DNA. The entirety of the evidence is needed to know what any result means.

2. Is it possible for a rape to happen and for no useful DNA evidence to be left behind? Put another way, if someone says she was raped, but no DNA evidence supports her claim, does that prove she made a false rape report?

I answered this above but unless the victim stated that she was sure there no condoms used the absence of DNA could not prove she was mistaken much less that she made a false report.

3. I’ve seen it claimed that mixed DNA from multiple rapists will not necessarily match the individual DNA of any of the rapists, so multiple rapists not using condoms may be unidentifiable. This seems dubious to me. Do you know if this is true?

Mixed DNA from more than one individual never “matches” a single person. Instead if all of a person’s DNA types are found in the mixture then they cannot be excluded as potential contributors. If two people donate DNA then all of their “alleles” or markers will be there so as many as four per locus (genetic site) of which there at least 15 that can be tested. If three, four, or more people donate DNA then there will be so many alleles in a mixture that very few if any people can be excluded as potential contributors. In such an event the evidence does become useless.

4. Is it possible for a condom to be used, without physical evidence of condom use (traces of latex, etc) being left behind?

This question is better asked of a forensic chemist but I do know that such traces are often but not always left behind

Hope this helps,

Bill Shields

William C. Thompson
Dr. Thompson is a Professor in the Department of Criminology, Law and Society at the University of California, Irvine, and a member of the California Bar. He has been a member of the NACDL DNA Strikeforce and has represented a number of defendants in cases that utilized DNA evidence. His work into flaws with the Houston, TX Police Department Crime Laboratory has recently been featured prominently in stories by the television news show 60 Minutes.

1. If DNA evidence fails to prove that an accused person raped an alleged rape victim, does that prove that the accused person could not have raped the alleged victim?

NO. ABSENCE OF EVIDENCE IS NOT NECESSARILY EVIDENCE OF ABSENCE. ON THE OTHER HAND, IF THE ALLEGED VICTIM SAYS “THIS SEMEN STAIN WAS DEPOSITED BY THE DEFENDANT” AND THE TEST REVEALS THAT THE SEMEN STAIN WAS IN FACT FROM SOMEONE OTHER THAN THE DEFENDANT, OR THAT IT IS NOT A SEMEN STAIN, THAT WOULD RAISE DOUBTS ABOUT THE VERACITY OF THE ALLEGED VICTIM.

2. Is it possible for a rape to happen and for no useful DNA evidence to be left behind? Put another way, if someone says she was raped, but no DNA evidence supports her claim, does that prove she made a false rape report?

NO. A RAPIST WHO FAILED TO EJACULATE OR USED A CONDOM MIGHT LEAVE TOO
LITTLE BIOLOGICAL MATERIAL BEHIND FOR IT TO BE DETECTED.

3. I’ve seen it claimed that mixed DNA from multiple rapists will not necessarily match the individual DNA of any of the rapists, so multiple rapists not using condoms may be unidentifiable. This seems dubious to me. Do you know if this is true?

IT DEPENDS ON THE WAY THE ANALYST CHOOSES TO INTERPRET THE MIXED PROFILE. IN THE CASES I LOOK AT, THE ANALYST ARE USUALLY QUITE LENIENT ABOUT WHAT THEY WILL CALL A “MATCH.” A MIXTURE OF DNA FROM THREE OR MORE MEN CAN OFTEN BE INTERPRETED IN A MANNER THAT ALLOWS A VERY SUBSTANTIAL FRACTION OF THE MALE POPULATION TO BE “INCLUDED” AS A POTENTIAL CONTRIBUTOR.

4. Is it possible for a condom to be used, without physical evidence of condom use (traces of latex, etc) being left behind?

YES

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69 Comments »

  1. This post is too short. You should bulk it up next time, with some resources or citations or something, instead of just pithy one-liners.

    (Blink.)

    Excellent rundown of the issue. It seems to strengthen the rightness of the “let’s wait and see what the evidence says” point of view.

    Comment by Robert — April 15, 2006 @ 3:37 am | Reply

  2. I find the reporting on this issue annoying. When we hear reports about “the DNA evidence” not matching any of the accused men what exactly do they mean by “the DNA evidence”?

    Is it that

    1) DNA evidence of the type you would expect from a rape (eg semen) was found but it definitely doesn’t match any of the men tested;

    2) DNA evidence of the type you would expect from a rape was found but it doesn’t definitely match any of the men tested;

    3) DNA evidence not indicative one way or another of rape (eg non-pubic hair in a non-private area) was found and it definitely doesn’t match any of the men tested;

    4) DNA evidence non indicative one way or another of rape was found and it doesn’t definitely match any of the men tested;

    or

    5) we don’t know which of the above (if any) was found but whatever was found doesn’t definitely match any of the accused;

    1) tends to exonerate certain men fairly strongly, 2) tends to exonerate but less strongly, 3) tends to exonerate fairly strongly, 4) tends to exonerate less strongly and 5) is pretty much meaningless. I’m leaning toward 5) as the real answer for now, which makes the media reports ‘exonerating’ people very premature.

    Comment by Sebastian Holsclaw — April 15, 2006 @ 4:22 am | Reply

  3. Rape is, contrary to popular belief, an extremely difficult crime to prove in a courtroom;

    You’ve just made a compelling case for its being difficult to disprove too. That leaves only one leg of Hale’s maxim in dispute.

    Comment by Daran — April 15, 2006 @ 4:43 am | Reply

  4. Yeah, tell that to all the trolls who were protesting that these guys are innocent, innocent, innocent. Doesn’t matter if a guy gets convicted: there are people who will shout he was framed.

    Comment by ginmar — April 15, 2006 @ 12:08 pm | Reply

  5. People saying they must be innocent are just as premature as those saying they must be guilty.

    There will always be people saying nutty things.

    Comment by Robert — April 15, 2006 @ 12:10 pm | Reply

  6. Yeah, except you’re ignoring that there’s a corresponding history of calling women lying sluts at the same time, and that does NOT go away.

    Comment by ginmar — April 15, 2006 @ 12:19 pm | Reply

  7. Sure. There’s a lot of sexism out there.

    That wrong approach has no bearing on what the correct approach to looking at these cases is – which is to wait to see the evidence.

    Comment by Robert — April 15, 2006 @ 12:24 pm | Reply

  8. I look at everything in a Zioracial angle.
    What do the Zionists think and how will they expliot this is to further dehumanify European American society? That is the main issue at hand. Bush looks at European Americans the same the Zionist angle, if they will not willingly and happily expend themselves for the Chosen people in their wars, they are evil. Bush and Zionist Elite are united against the white serf and will use any propaganda tool necessary.

    Comment by Justice for Palestine — April 15, 2006 @ 10:48 pm | Reply

  9. I look at everything in a Zioracial angle. What do the Zionists think and how will they expliot this is to further dehumanify European American society?

    Damn those Zionists! Those guys are tenacious. Just the other day I had my European Americanness dehumanized by the Zioracialists.

    Either that or I had too many whiskey shots and I threw up in the hallway. I forget which it was.

    Comment by Robert — April 16, 2006 @ 1:21 am | Reply

  10. I want to comment on a few things in this otherwise well-researched and thoughtful article. I apologize in advance for speaking rather bluntly about a crime as grisly as rape as some of the things I say may seem very crass.

    Regarding glycogen: DNA can be extracted from almost any cell, even those that do not contain glycogen. Testing for cells that contain glycogen helps determine the source of epithelial cells.

    Cells from a person’s mouth do not generally contain glycogen, cells from a person’s vaginal vault do. Rape cases sometimes require determining the source of epithelial cells.

    While I agree that the absence of evidence is not proof of absence, we can’t at the same time pretend that the negative result is meaningless.
    That no DNA appears to have been found is troubling, and as the case develops we’ll be able to place the result in context.

    What I am really troubled about is the fact that people appear to be making things up. Several media reports quote the District Attorney as saying that DNA is recovered in only 20-25 percent of rape cases. A DOJ study was mentioned in support of this. I cannot find this study, and I’ve been hunting for it. I now believe that this statistic is pure fantasy.

    There is a DOJ study that says DNA was _submitted_ in only 20-25% of rape cases, but this study was an expose of how much biological evidence goes unanalyzed, not how much is truly impossible to recover.

    And yes, I do work in the field. I’ve written another article on the topic, the website link will take you there.

    B

    Comment by B — April 18, 2006 @ 1:47 am | Reply

  11. The comments here don’t mention the reported fact that the police lab also tested for male DNA under the accuser’s fingernails, and found none there, either. Yet the accuser reportedly alleged that she scratched the alleged assailants with her fingernails.
    Another point: I’d like to hear an expert speak to this question: how likely is it that *three* men could rape someone without leaving a trace of DNA?

    Comment by wumhenry — April 18, 2006 @ 1:43 pm | Reply

  12. How reliable are the vagueries of what DNA can indicate weighed against a claim of 100% positive identification of an individual who
    was, without doubt, not present at a crime scene?

    Comment by CaptDMO — April 19, 2006 @ 5:36 pm | Reply

  13. Another point: I’d like to hear an expert speak to this question: how likely is it that *three* men could rape someone without leaving a trace of DNA?

    This is an excellent question! If we calculate the odds of a rapist getting lucky and leaving no DNA on the alleged victim as a 1:100 occurance, then for this case we’re looking at a 1:1,000,000 phenomona.

    Comment by TangoMan — April 19, 2006 @ 8:58 pm | Reply

  14. > how likely is it that *three*
    > men could rape someone without leaving a trace of DNA?

    In a general sense, it’s impossible to answer that question. Too many variables regarding the specifics of the crime would have to be spelled out. There are factors that seem to work in both directions.

    My entire point was that while it is difficult to pin down what the “absence of evidence” means, we shouldn’t fool ourselves into thinking it’s meaningless. It’s a fragment of the entire body of evidence.

    forensicthinking.blogspot.com has more on this.

    Comment by B — April 19, 2006 @ 8:58 pm | Reply

  15. > This is an excellent question! If we calculate the odds
    > of a rapist getting lucky and leaving no DNA on the
    > alleged victim as a 1:100 occurance, then for this case
    > we’re looking at a 1:1,000,000 phenomona.

    This strikes me as wishful thinking.

    When this case broke, I discussed it with a few coworkers to get a sense of how often the sexual assault cases that they work have DNA present.

    The rough approximation that is no substitute for a real study is around 50% of cases have some semen, which in turn leads to a positive DNA result.

    so 1/2 * 1/2 * 1/2 is only 1/8, not very unusual at all. if it sounds rare to you, think how common families with three girls or three boys are (I assure you they are quite common).

    Even if the probability was 1/5th that amount, 1/10 for a rapist not to leave DNA, we’re looking at probability of:

    1/10 * 1/10 * 1/10, which is 1/1000. Sounds rare, but when you’re dealing with the numbers that rape unfortunately stacks up, it will occur surprisingly often.

    B.

    Comment by B — April 19, 2006 @ 9:07 pm | Reply

  16. DNA is more than semen. DNA can be present without semen. Recall that DNA was collected in this case and sent to the lab.

    Also, your coworkers estimates likely reflect the victims showering after the rapes, reports that happen days, weeks, months, or years after the crime. The most relevant category would be rapes where the evidence is collected from the victim shortly after the commission of the crime, where the medical examiners report that DNA has successfully been collected and where suspect DNA samples are compelled by the court in order to allow suspects to be excluded.

    This alleged victim reports that she scratched some of the alleged rapists yet no DNA is found in the scrapings from underneath her fingernails. Three men allegedly raped her yet all 3 failed to leave behind semen, public hair, body hair, skin cells, saliva, and other sources of DNA, not just within her anus and vagina, but all over her body. In the case of a single rapist such absense of DNA traces would be a low probability event, but the probability of all 3 alleged rapists each getting so lucky is quite astounding.

    We didn’t read reports of the alleged victim going home to shower or change clothes. IIRC, standard procedure is for the hospital to bag the clothes so they can be analyzed for DNA traces, thus we’d be looking at her clothes as constraining the destruction of DNA traces. Discharges aren’t thrown into the toilet – they’re captured by her clothes. Suspect epithelial cells would likely still be on her hips, breasts, inner thighs, or transferred onto her garments.

    Keep in mind that the prosecutor had reason to be expecting positive results – the alleged victim went to the hospital and was processed by medical professionals and the reports concerning the DNA evidence collected were indicative that someone would be identified.

    Therefore, my contention was that one alleged rapist could get lucky by not leaving DNA that would be recovered a few hours later, but 3 guys gettting just as lucky really stretches the odds.

    We’re being asked to believe that these guys wore condoms, wore latex gloves, didn’t break a sweat during the sex act, didn’t spray saliva in their fury, drunkenness, or excitement, didn’t drop a hair, etc. Perhaps they wore a “Naked Gun” Full Body Condom.

    Caveat: The facts and the definitions we’re reading about in this case are quite open to interpretation, so we really don’t know what the prosecutor meant when it was reported that “DNA was recovered” or “injuries consistent with rape.”

    Comment by TangoMan — April 19, 2006 @ 10:08 pm | Reply

  17. Keep in mind that the prosecutor had reason to be expecting positive results – the alleged victim went to the hospital and was processed by medical professionals and the reports concerning the DNA evidence collected were indicative that someone would be identified.

    The lawyer for Flannery stated that he had not received the results of the rape kit yet, so it is possible that there was some sort of trace evidence found upon her clothing that was not reported to the defense. That might explain why the two young men were indited. Also, the second set of DNA results have not come back yet. Though it is highly unlikely they would differ from the previous results, it is still possible for them to match with the two accused.

    I agree with B. The absence of DNA evidence should not be considered meaningless.

    Comment by Toy Soldier — April 19, 2006 @ 10:46 pm | Reply

  18. Face it. This trashy stripper made the whole thing up due to her anger that a bunch of white men yelled racial slurs at her. She has no right to use her anger to break the law – this is not her first crime remember….. She is a lying piec of trash. You will see I am right soon. I hope she pays the price for this – it is bimbos like this that make all women who WERE raped have to go through hell getting people to believe them.

    Comment by Gina Pasconi — April 19, 2006 @ 11:34 pm | Reply

  19. B.

    I don’t mean for my comment to come across as telling you how things are done in your profession 🙂 What I meant to convey was that the probabilities involved with all 3 alleged rapists not leaving DNA traces when they would likely have had different rape dyamnics in the alleged rape – one guys was supposedly scratched by the alleged victim, another guy may have held her arms in a restraining manner, another guy may have . . you get the idea.

    How often do you or your co-workers run into “No DNA Recovered” situations just hours after the rape and with multiple rapists involved? I’d be very interested in the odds involved in these types of situations.

    Comment by TangoMan — April 19, 2006 @ 11:38 pm | Reply

  20. The absence of DNA evidence should not be considered meaningless.

    Of course not. But it’s equally ridiculous to pull statistics out of our butts to claim there’s a one in one million chance the accuser is telling the truth, or to assume that the defense attorneys are giving us the straight dope on the evidence. The prosecution is keeping quiet–as it should be, rather than trying the case in the newspapers.

    Comment by mythago — April 20, 2006 @ 11:12 am | Reply

  21. But it’s equally ridiculous to pull statistics out of our butts to claim there’s a one in one million

    The point of the “statistic” was to illustrate that this situation is akin to rolling double sixes three times in a row. Assign your own odds to a “No DNA” event and then cube them.

    Comment by TangoMan — April 20, 2006 @ 1:59 pm | Reply

  22. >>it is possible that there was some sort of trace evidence found upon her clothing that was not reported to the defense. That might explain why the two young men were indited>it’s equally ridiculous … to assume that the defense attorneys are giving us the straight dope on the evidence. The prosecution is keeping quiet–as it should be, rather than trying the case in the newspapers

    Comment by wumhenry — April 20, 2006 @ 6:21 pm | Reply

  23. I didn’t do that right. I’ll try again.

    “it is possible that there was some sort of trace evidence found upon her clothing that was not reported to the defense. That might explain why the two young men were indited”

    But the prosecutor said that the indictments were based on “100% certain” identification from photographs.

    “it’s equally ridiculous … to assume that the defense attorneys are giving us the straight dope on the evidence. The prosecution is keeping quiet–as it should be, rather than trying the case in the newspapers”

    Where have *you* been? The prosecutor, who is campaigning for re-election and would, no doubt, like to keep this pot boiling till the ballots are cast next month, made conclusory and inflammatory statements to the press right from the get-go. He said, for instance, that he was sure that the accuser was raped, and he predicted that the DNA results would prove guilt. I think we can safely assume that if the defense lawyers were lying about the findings (which would have been an incredibly stupid tactic) the DA would have contradicted them.

    Comment by wumhenry — April 20, 2006 @ 6:31 pm | Reply

  24. Yes, and after he said there was a rape and the DNA would show evidence of it, his office has stopped granting interviews.

    And no, it wouldn’t have been an ‘incredibly stupid tactic’ at all for one of the defense lawyers to exaggerate or misstate what the DNA results said. Why do you think it would be? The defense lawyer would, what, get hauled in for perjury? A jury would convict their clients?

    Comment by mythago — April 20, 2006 @ 7:03 pm | Reply

  25. So it’s settled then. There was absolutely no DNA evidence recovered from the alleged victim. Or there was, but it quite definitely excluded all the Lacrosse Players. Or maybe only some of them, the ones represented by the lawyer making the statement. Or perhaps they weren’t positively excluded, just not included, an inconclusive result. Or maybe…

    Can anyone tell me – citing a source preferably more authoritative than an anonymous blog comment – exactly what it is claimed that the DNA results do or don’t show? Because right now all I’m seeing is different people’s interetations of a Rorschach inkblot.

    Comment by Daran — April 20, 2006 @ 10:55 pm | Reply

  26. As I recall, and feel free to correct me, the DNA results were “inconclusive”.

    Comment by mythago — April 20, 2006 @ 11:16 pm | Reply

  27. I think it really won’t be possible to know exactly what the DNA evidence is, and what it says, until we have the evidence fully presented in a courtroom environment, with both sides having a chance to examine it.

    Tangoman wrote:

    The point of the “statistic” was to illustrate that this situation is akin to rolling double sixes three times in a row.

    And you know that about the situation because..? Oh, yes. Because you’ve pulled that knowledge out of nothing.

    Do you know if the rapists used condoms or not? Because I would think that would make a difference to your oh-so-scientific method of evaluating evidence. Since you seem to know, let us know what’s the case, and link to the source of your knowledge.

    Do you know if it’s the case that no pubic hairs, DNA, etc, was found; or is it just the case that there was some found, and initial tests failed to establish a connection to any LAX team member? You seem to know for a fact that it’s the former. Link to your source, please. I hope it’s better than some comment made by a defense attorney.

    Comment by Ampersand — April 21, 2006 @ 1:28 am | Reply

  28. I don’t find it fruitful to debate intellectual cowards. They’re full of bluff, bravado, and easily swayed by faulty logic.

    Comment by TangoMan — April 21, 2006 @ 2:59 am | Reply

  29. Come on TangoMan. While I don’t agree with Amp’s decision on banning you from Alas (I think it sucks, but not my blog, so…), I hope you can see that comment you just made is full of bluff and bravado.

    Amp asked for a source, if you have it, show it. Otherwise people will conclude that the one full of bluff is not Amp.

    Daran:

    Because right now all I’m seeing is different people’s interetations of a Rorschach inkblot.

    Yep, me too. Patience. All the facts are not known. The possibility of rape could still turn out any way: Guilty or not guilt, as can the possibility of Mary Doe making a false accusation: Guilty or not guilty.

    If I were a betting man I’d say that likely (from the facts so far) is that guilt of either can not be proven beyond reasonable doubt, which I suspect is quite common, and not an unreasonable outcome.

    Comment by Tuomas — April 21, 2006 @ 3:27 am | Reply

  30. “no, it wouldn’t have been an ‘incredibly stupid tactic’ at all for one of the defense lawyers to exaggerate or misstate what the DNA results said. Why do you think it would be? The defense lawyer would, what, get hauled in for perjury? A jury would convict their clients?”

    No, the DA have the lab release the results to the press, and the defense lawyers would be exposed as liars.

    Comment by wumhenry — April 21, 2006 @ 11:45 am | Reply

  31. No, the DA have the lab release the results to the press, and the defense lawyers would be exposed as liars.

    The defence lawyers then complain to the court that the DA’s actions tainted the jury pool.

    Comment by Daran — April 21, 2006 @ 12:03 pm | Reply

  32. Yep. Not to mention that whether the defense attorneys’ statements now contradict what the DNA may show later means zero in a criminal trial. Lawyers’ statements are not evidence. The DA is not going to be allowed to tell the jury “You heard counsel for the defense tell Geraldo Rivera that…. But as we can see, the evidence shows that….”

    Please note that I’m not saying what members of the defense have told the media means anything one way or the other about the actual guilt of the accused. I’m just noting that it’s a tactic, because their job is to exonerate their clients.

    Comment by mythago — April 21, 2006 @ 12:13 pm | Reply

  33. I doubt that Nifong would’ve been slammed for tainting the jury pool if he’d authorized release of the DNA results. TO the contrary, I’ve read that such information is routinely made available to the press. Besides, I don’t think that the possibility of “tainting the jury pool” would have fazed Nifong at that point (i.e., after defense lawyers talked about the DNA results). He crossed that line a long time ago.

    mythago, your premise is correct, but it doesn’t support your contention that it could’ve been in the defense lawyers’ interest to lie about the DNA results. The objective was obviously to get more sympathetic news coverage for their clients, and it would have backfired severely if Nifong & friends had given it the lie. Besides handing a huge PR victory to the prosecutor on a silver platter, the defense lawyers would forfeit any reputation for honesty and might be at risk of debarment.

    Comment by wumhenry — April 21, 2006 @ 6:49 pm | Reply

  34. Therefore, my contention was that one alleged rapist could get lucky by not leaving DNA that would be recovered a few hours later, but 3 guys gettting just as lucky really stretches the odds.

    Ahh, but TangoMan, you have no idea what the odds are. You know what you want them to be, but that’s not the same thing.

    You’re correct in that DNA from an attacker can be left in other sources than semen. Most of the other sources such as pubic hair, saliva traces, fingernail scrapings etc. are harder to find and the results are more problematic to interpret.

    The resulting DNA profiles are usually a mixture of the victim and the attacker(s). Semen traces are unique in that sperm are chemically disticnt such that they can be extracted differentially from other cells – the DNA profiles are often not mixtures thanks to that.

    If we take Nifong’s 20-25% number at face value and cube it, we’re still dealing with an event that is to be expected in at last one out of 125 rapes, or roughly 760 of the approximately 95,000 rapes that occurred last year.

    Not likely, but not impossible either.

    If it’s true that no DNA from alleged assailant(s) was found at all, this will play very strongly in the “reasonable doubt” area – as I think that it should.

    We shouldn’t at the same time exaggerate this into “she lied” either.

    B.

    Comment by B — April 23, 2006 @ 3:43 am | Reply

  35. The objective was obviously to get more sympathetic news coverage for their clients

    No. The goal is to bias the jury pool. Throwing out a kitchen sink of theories (especially when the DA is in lockdown mode) is a way of getting those ideas out into the public, so that if you need to present one at trial, hopefully your jurors will think “Oh yea, I heard that before…”

    On what grounds do you think exaggerating, stretching or just plain misstating the evidence would lead to disbarment?

    Comment by mythago — April 23, 2006 @ 3:57 pm | Reply

  36. “The goal is to bias the jury pool.”

    Rubbish! The jurors will see the *actual* DNA-test findings in the trial. In the unlikely event that the findings positively incriminate one or more defendants, are the jurors going to discount that merely because defense lawyers said in pre-trial press statements that the results were negative?? Get real.

    Comment by wumhenry — April 25, 2006 @ 10:47 am | Reply

  37. “In the unlikely event that the findings positively incriminate one or more defendants, are the jurors going to discount that merely because defense lawyers said in pre-trial press statements that the results were negative?? Get real.”

    It’s true, in that event, the line the defense has been feeding the press won’t do much good.

    However, in the not-especially-unlikely event that the DNA results are inconclusive, the defense wants to bias the jury pool with the idea that inconclusive DNA “proves” the defendants must be innocent.

    Comment by Ampersand — April 25, 2006 @ 1:10 pm | Reply

  38. Ampersand: However, in the not-especially-unlikely event that the DNA results are inconclusive, the defense wants to bias the jury pool with the idea that inconclusive DNA “proves” the defendants must be innocent.

    Why bother trying to prove innocence when all need be done is defend against criminal conviction? Who cares if the man on the street can’t distinguish between the two?

    It seems to me that you make the distinction quite clearly, Ampersand. What I don’t get is why you’re so apparently dead set that, in the absence of evidence to convict, we should nonetheless weigh heavily against the accused in the realm of public opinion. As the likelihood of anything evil or criminal having occured diminishes with each new revelation of lack of evidence, you appear to be grasping and hanging on by a thread because innocence can’t be proved.

    I can’t prove that a UFO didn’t just land in Central Park and subsequently erase our memories of the event, either. But I’m not going to hold to the belief because it can’t be proved not to be true.

    Comment by Brutus — April 25, 2006 @ 2:20 pm | Reply

  39. Ampersand is a feminist, and of a sort that is heavily invested in the idea that 99% of women simply do not lie about rape. The number of women who are proved to actually lie about rape is shoehorned into the category of bizarre cases or the occasional profoundly mentally ill person. It would threaten his worldview to find that substantial numbers of women will lie about rape, just as they will lie about anything else.

    I hasten to say that in my own view, both men and women will lie about a great number of things, of equal or even greater seriousness to rape. My jaundiced eye for humanity is not gendered, in other words; I think there are a lot of men lying about big stuff too; there are around the same number of dishonest men as women. Rape just stands out in the public’s attention.

    Amp’s liberalism also requires him to give extra credence to the testimony of a black person. This is an understandable bias to have, particularly given the indubitable history of the testimony of black people being derogated and devalued.

    Is it possible that this particular woman is telling the truth? Absolutely. That shouldn’t be put into question. Is it possible that she’s lying as part of some scam or operation that’s gone awry? Sure. Can we tell from here which is true? No. I’m sticking with agnosticism, although privately I’ve got a guess as to what happened that isn’t flattering towards any party involved.

    So Amp’s position is perfectly tenable; it’s just a risky one, in that he runs a substantial risk that his credence in this person will prove unfounded. As it only his own credibility in the balance, however, there is no harm being done to society by him taking the position he’s taken.

    Leave him to his delusions, is the uncharitable way of phrasing what I’ve said.

    Comment by Robert — April 25, 2006 @ 2:47 pm | Reply

  40. Brutus:

    As the likelihood of anything evil or criminal having occured diminishes with each new revelation of lack of evidence, you appear to be grasping and hanging on by a thread because innocence can’t be proved.

    Assuming that defense claims of lack of evidence are true, then the likelihood does indeed diminish, but not to zero. Lack-of-evidence does not trump evidence, and we do have evidence, in the form of her injuries, both consistent with a rape, and consistent with a beating. To prevail, the defence will have to present an account of the night’s events consistant with this evidence, and sufficiently plausible not to be dismissed out of hand. At the moment, the defense’s version of events – she arrived already injured (already raped? – seems fundamentally implausible. That might change if the evidence they claim to have – time-stamped photos, etc – can stand up to scrutiny, but we haven’t seen that evidence yet.

    I can’t prove that a UFO didn’t just land in Central Park and subsequently erase our memories of the event, either. But I’m not going to hold to the belief because it can’t be proved not to be true.

    Yet you hold to the contrary belief – that a UFO did not do this, and would probably demand extraordinary evidence before you would be prepared to change your mind. One of the two unprovable beliefs is inherently more plausible than the other.

    Robert:

    Ampersand is a feminist, and of a sort that is heavily invested in the idea that 99% of women simply do not lie about rape.

    That’s hardly contentious is it? If you add the percentage of women who do not report being raped to the percentage who make truthful reports, then you’re unlikely to be far off 99% no matter what the ratio of truthful reports to false reports.

    No doubt what you meant was that (in Ampersand’s view) 99% or thereabouts of women who report being raped are truthful about it. But by framing the point as you did, you turned a legitimate question about the frequency of false rape allegations into an unreasonable aspersion cast at all women. I don’t know whether that was your intention, but such dishonest framings are typical of and deliberate in antifeminist rhetoric in general.

    It certainly is feminist dogma that only a tiny proportion of rape reports are false. The ‘statistic’ most often bandied around is 2%. I have addressed the source and validity of this figure at length in my posts to Alas (I can’t be bothered to look them up right now). The conclusion in short is that it is an utterly bogus figure. Despite demonstrating this conclusively, the response I got from almost every feminist commentator was blank staring disbelief, sometimes accompanied by personal abuse.

    Ampersand was the exception to this rule. He was the only one prepared to engage me in an honest evidence-based debate. My recollection of the conclusion of that debate is that he is not wedded to the idea that only a tiny fraction of rape reports are false. Rather he would argue that the evidence, such as it is, is weak and conflicting, hence inconclusive.

    The number of women who are proved to actually lie about rape is shoehorned into the category of bizarre cases or the occasional profoundly mentally ill person. It would threaten his worldview to find that substantial numbers of women will lie about rape, just as they will lie about anything else.

    Again, while that is a fair criticism of feminism in general, I find Ampersand to be an exception. Nevertheless, both he and I would point out that there is no evidence that a large proportion of rape accusations (i.e allegations which identify an alleged perpetrator) are maliciously false (i.e made with the intention of harming the falsely accused) or that a large proportion of rape convictions are false, or that ‘lying women’ are a significant contributory factor to them. Antifeminist debate is characterised by the dishonest conflation of these ideas – The (weak and conflicting) evidence of a relatively large proportion of false allegations is selectively cited, incorrectly and dishonestly characterised as evidence of false accusations and used to support claims that a large proportion of convictions are false, and that ‘lying women’ are the primary cause of this.

    Comment by Daran — April 26, 2006 @ 9:09 pm | Reply

  41. Yes, Amp is a lot more willing than most people to look at contrary evidence. But he’s still human, and it takes a lot of contrary evidence to stir him from his positions. (Which is reasonable, of course.)

    I accept your reframing of my remarks as far as removing the (unintentional) structural similarity to “anti-feminist” rhetoric. I’m interested in knowing what the truth is, more than I’m interested in making life uncomfortable for feminist rhetoricians.

    Comment by bobhayes — April 26, 2006 @ 9:49 pm | Reply

  42. “At the moment, the defense’s version of events – she arrived already injured (already raped? – seems fundamentally implausible.”

    What’s fundamentally implausible about her having rough sex earlier the same day?

    Speaking of implausibility. The accuser alleges that Seligman — whom she identified with “100% certainty” from photos — and two others had their way with her in the bathroom for 30 minutes after she and her colleague left the house and then went back in. A neighbor who evidently is no fan of the lacrosse team said that he saw them go back into the house at approximately 12:30AM. There’s ironclad proof that Seligman called a cab at 12:14, and the cabbie said he found Seligman standing at a streetcorner about four minutes later, took him to an ATM, a restaurant, and dropped him off at his dorm. If the accuser re-entered the house any time after 12:14, she’s a goddam liar.

    Comment by wumhenry — April 28, 2006 @ 7:11 pm | Reply

  43. wumhenry:

    “At the moment, the defense’s version of events – she arrived already injured (already raped? – seems fundamentally implausible.”

    What’s fundamentally implausible about her having rough sex earlier the same day?

    Nothing. However she did not merely have rough sex. She was beaten up. That she had these injuries does not appear to be in dispute.

    Now it’s not implausible that she was beaten up earlier in the day. It is implausible that having been beaten up, instead of accusing the person who did that to her, she would go off and accuse someone else. It’s not impossible, it just seems unlikely.

    Speaking of implausibility. The accuser alleges that Seligman — whom she identified with “100% certainty” from photos — and two others had their way with her in the bathroom for 30 minutes after she and her colleague left the house and then went back in. A neighbor who evidently is no fan of the lacrosse team said that he saw them go back into the house at approximately 12:30AM. There’s ironclad proof that Seligman called a cab at 12:14, and the cabbie said he found Seligman standing at a streetcorner about four minutes later, took him to an ATM, a restaurant, and dropped him off at his dorm.

    Have you seen this ‘ironclad’ proof? I said earlier that I would give no credence to defense attornies’ statements to the media about evidence not in the public domain, (nor prosecutors’. Affidavits are evidence. Show me one and I’ll consider it). But even if I did, I am slightly at a loss as to how a taxi driver’s eye-witness identification can be considered to be ‘ironclad’ given all we know about the unreliability of such identification. I took a taxi myself a couple of days ago, and I can recall nothing more of the driver’s features than that he was male and white. I simply do not believe that the driver in this case would have paid sufficient attention to the appearance of his client to make a firm identification. Without that identification, we can’t know that the person who used Seligmann’s phone and bank and pass cards was Seligmann.

    If the accuser re-entered the house any time after 12:14, she’s a goddam liar.

    So you live in a world where statements are either true or goddam lies; there is no possibility of a firmly held but mistaken belief?

    In fact the remarks I made about the taxi driver’s identification of the suspect applies equally well to the alledged victim. She could, without lying, have been mistaken in her identification of Seligmann. His alabi, if it holds up, cannot prove that she wasn’t raped at the party, it can only prove that she wasn’t raped by him.

    Comment by Daran — May 1, 2006 @ 7:52 pm | Reply

  44. bobhayes:

    I accept your reframing of my remarks…

    I was replying to “Robert”. Are you and he the same person?

    I’m interested in knowing what the truth is, more than I’m interested in making life uncomfortable for feminist rhetoricians.

    I try to do both. 🙂

    Comment by Daran — May 1, 2006 @ 8:01 pm | Reply

  45. “However she did not merely have rough sex. She was beaten up. That she had these injuries does not appear to be in dispute.”

    Exactly what kind of injuries were found that were inconsistent with rough sex (which can include strangulation)?

    “I would give no credence to defense attornies’ statements to the media about evidence not in the public domain, (nor prosecutors’. Affidavits are evidence. Show me one and I’ll consider it).”

    Well, then, what do you have to talk about? For the sake of discussion pending the trial, I’m going on the working assumption that descriptive statements about evidence by defense lawyers that aren’t contradicted by the DA are true, and vice versa. It won’t help their clients’ case for defense lawyers to lie about evidence, and if they do they will likely put themselves in professional-ethics hot water.

    “But even if I did, I am slightly at a loss as to how a taxi driver’s eye-witness identification can be considered to be ‘ironclad’ given all we know about the unreliability of such identification.”

    What about the phone record showing that he received a call from Seligman’s cellphone at 12:14?

    “So you live in a world where statements are either true or goddam lies; there is no possibility of a firmly held but mistaken belief?”

    I live in a world where there may or may not be a plausible possibility that a false statement results from a mistaken belief — depending on the circumstances. In this case, it’s not bloody likely that the accuser made an honest mistake when she fingered Seligman’s photo with “100% certainty”. If Seligman is innocent, then in order to believe the rape story you have to believe that when the accuser was shown photographs of all the possible suspects — including the three guys who actually raped her — she picked someone who did NOT rape her and was 100% certain of the identification. If there were a confusing resemblance between Seligman and an actual culprit she’d presumably say “it was definitely either this guy or that guy but I’m not sure which.”

    Comment by wumhenry — May 3, 2006 @ 12:08 pm | Reply

  46. “Without that identification, we can’t know that the person who used Seligmann’s phone and bank and pass cards was Seligmann.”

    Ah. Cleverly anticipating that he would be accused of rape and that there would be evidence establishing a time-window for the crime that would close after 12:30, Seligman called a cab for another partier and prevailed upon him to take and use his ATM card on the way back and use Seligman’s student ID card to enter Seligman’s dormitory at 12:46. Can’t say it’s impossible, but it’s rather far-fetched.

    Comment by wumhenry — May 3, 2006 @ 12:29 pm | Reply

  47. That doesn’t seem all that far-fetched, wumhenry. If you plan to commit a crime and are smart, you think about establishing an alibi. Putting a co-conspirator in a cab is a pretty simple technique.

    Comment by Robert — May 3, 2006 @ 1:27 pm | Reply

  48. “That doesn’t seem all that far-fetched, wumhenry. If you plan to commit a crime and are smart, you think about establishing an alibi.”

    Would a shrewd perp who wants to rape a stripper and get away with it invite a *second* stripper to the same gig and commit the crime within the earshot of several dozen witnesses — even if they happen to be teammates of his? If these guys are guilty, they were anything but clever.

    Comment by wumhenry — May 3, 2006 @ 4:01 pm | Reply

  49. A large, loud, noisy party is the ideal environment to perpetrate some kind of group crime. And a second stripper makes a great diversion, to draw the attention of anyone not in on the plan.

    Comment by bobhayes — May 3, 2006 @ 4:14 pm | Reply

  50. I beg to differ. From a wouldbe perp’s perspective, a second stripper is a loose cannon.

    Anyway, this line of conjecture started with the notion that Seligman might have arranged for someone else to take the taxi, use the ATM card, and enter the dorm with his ID card. I just read on Fox News (and if you don’t like Fox I’m sure you can read it elsewhere) that the defense says it has time-stamped photos from the ATM security cam showing *Seligman* using the machine at the time in question. What are you going to say now: that he commissioned a secret identical twin to go to the ATM?

    Another noteworthy factoid: phone-company records reportedly show that no less than NINE calls were placed from Seligman’s cellphone between 12:05 and 12:14. I think that pretty-well leaves Seligman, or his secret identical twin, out of the picture for *that* time-period.

    Comment by wumhenry — May 3, 2006 @ 4:30 pm | Reply

  51. If there is a time-stamped photo of Seligmann at a different venue than the rape, at the time reported for the rape, then that would be a pretty ironclad alibi. I’m not sure why you’re thinking I’m going to go to some lunatic extreme to prove his guilt; I have no idea of his guilt or innocence. I am merely arguing from logic.

    The existence of calls placed from his cellphone have no probative value. (Recordings of those calls probably would have.) Anybody can use a cellphone. He could have been making those calls in mid-rape to gloat to a buddy about what he was doing. Or he could have made those calls from the backseat of the cab, calling his widowed mother to make sure she got home all right from the church social. It’s not evidence; it’s data. You seem to have a hard time telling the difference.

    Comment by bobhayes — May 3, 2006 @ 5:25 pm | Reply

  52. Making a phone call while copulating would definitely interfere with enjoyment of the activity for yours truly. I find distraction most unwelcome at such times. And I doubt that I’m atypical in this respect.

    I don’t have a problem with your logic, but common sense doesn’t seem to be your strong suit.

    Comment by wumhenry — May 3, 2006 @ 5:38 pm | Reply

  53. I think drawing conclusions from this level of micro-speculation serves little purpose, becuase we don’t have full enough access to the evidence, and the evidence we do hasn’t been tested by being questioned in court, under oath, by opposing council.

    However, from what we do know, it’s not hard to put together a story in which rape was preconcieved by at least one rapist. According to the second dancer, the first dancer, Mary Doe, was fine when she arrived but seemed incredibly knocked out when she left. From this many people have speculted that Mary Doe may have been drugged. When Mary Doe arrived the players gave drinks to both dancers, but only Mary Doe drank hers; the other one got spilled. So one possibility is that the intent may have been to drug and rape both dancers, but only Doe ended up getting drugged.

    But that’s just speculation; I make no claim to it being true. But it fits the known facts (which are not complete) at least as well as anything you’ve said, Wumhenry.

    Wumhenry wrote:

    In this case, it’s not bloody likely that the accuser made an honest mistake when she fingered Seligman’s photo with “100% certainty”.

    And you say this based on what expertise, exactly?

    In fact, there are literally hundreds of cases in which rape victims have, in apparent good intentions, ID’d innocent men with certainty under oath. Mistaken identification is the most common reason for false imprisonment.

    Maybe you think they’re all malicious liars. But criminologists don’t believe that; they say it’s simpoly easier to make a sincere but mistaken ID of an attacker than most people believe.

    Comment by Ampersand — May 3, 2006 @ 8:54 pm | Reply

  54. But in this case, as I stressed before, the accuser was presented with photos of all the possible — oh, just read the last paragraph of the message I sent yesterday at 12:08.

    Comment by wumhenry — May 4, 2006 @ 11:26 am | Reply

  55. While we’re at it:
    How is it apparent that the accusers in all those hundreds of cases were acting in good faith when they fingered innocent people?

    Although I don’t doubt that rape victims sometimes accuse innocent people by mistake, how often does it happen that a genuine rape victim picks an innocent person from a lineup that includes the actual perp? Not very, I’m sure.

    Comment by wumhenry — May 4, 2006 @ 11:38 am | Reply

  56. How is it apparent that the accusers in all those hundreds of cases were acting in good faith when they fingered innocent people?

    The assumption is that most women who report a rape and get DNA evidence taken are not sociopaths, and therefore would not purposely put a total stranger in prison. (Keep in mind that in most stranger rapes – unlike, I admit, the Duke case – there isn’t a possible story for why she’d wish the person convicted harmed if he hadn’t raped her).

    Also, it’s been shown that how the ID is run – for instance, making it double-blind rather than having it run by a cop who knows who the suspect is – significantly changes the odds of a false ID. That makes sense if false IDs are caused by good-faith error; it doesn’t make sense if the primary cause of false IDs is “malice.”

    I have absolutely no confidence that if some white jock beat me up on Monday I’d be able to successfully identify him from a photo line-up of forty-two white jocks three weeks later. Frankly, until I know someone for a few weeks, one fit young white guy with a short haircut looks pretty much like another fit young white guy with a short haircut.

    Besides, one of the most likely ways to produce a false ID is to tell a witness (or let the witness know through implication) that her attackers are definitely somewhere in this pile of photos – that puts pressure on her to recognize someone. A better-done photo ID would have included lots of photos of people with no relation to this case at all, and she should have been told that her attackers might not be among these pictures at all.

    Comment by Ampersand — May 4, 2006 @ 1:26 pm | Reply

  57. “I have absolutely no confidence that if some white jock beat me up on Monday I’d be able to successfully identify him from a photo line-up of forty-two white jocks three weeks later.”

    If you couldn’t, but picked one anyway and said you were 100% certain he was the perp, would you be: a)making an innocent mistake or b) lying?

    Comment by wumhenry — May 4, 2006 @ 2:09 pm | Reply

  58. “one fit young white guy with a short haircut looks pretty much like another fit young white guy with a short haircut”

    Really? I’ve only seen photos of two members of the Duke lacrosse team: Seligman and Finnerty. If you say that you can’t tell ’em apart I won’t believe it.

    Comment by wumhenry — May 4, 2006 @ 2:14 pm | Reply

  59. Still waiting for an answer to the second question in my 11:38 comment.

    Comment by wumhenry — May 4, 2006 @ 2:17 pm | Reply

  60. If you couldn’t, but picked one anyway and said you were 100% certain he was the perp, would you be: a)making an innocent mistake or b) lying?

    Me, personally? I’d be lying, because I’m aware that research has shown that false IDs are surprisingly easy for people to make.

    However, most people haven’t done the reading I have, and most people have no reason to suspect that witness ID is actually very unreliable, and that the “feeling” of certainty can be misleading.

    (By the way, as far as I know Mary Doe has never spoken directly to the press, and any quote from her you’ve heard is therefore thirdhand and of questionable accuracy. Yet you’ve been acting as if you know what she said to a certainty. If we applied the same harsh judgement to you that you apply to her, we’d call you a malicious liar. But I don’t think that would be a fair way to judge you, any more than it’s a fair way to judge her).

    I’ve only seen photos of two members of the Duke lacrosse team: Seligman and Finnerty. If you say that you can’t tell ‘em apart I won’t believe it.

    If you put them side by side, I can tell them apart. But if you put 42 photos of young white male jocks side by side, including different photos of Seligman and Finnerty, and told me to pick out those two gentlemen and no others, I don’t know if I’d be able to.

    Although I don’t doubt that rape victims sometimes accuse innocent people by mistake, how often does it happen that a genuine rape victim picks an innocent person from a lineup that includes the actual perp? Not very, I’m sure.

    Actually, I think test studies, done on college students, have shown that witnesses can pick the wrong person out of a line-up even if the right person is standing right there. (I can’t give you a citation; this is something I remember reading about in a criminology class 8 years ago.)

    You say “you’re sure.” What is your certainty based on? Do you have any research you can cite to support your view, for instance?

    Comment by Ampersand — May 5, 2006 @ 12:35 am | Reply

  61. line of conjecture

    Since the prosecution hasn’t revealed what evidence has led to maintaining charges, all of this is pretty much conjecture.

    From a wouldbe perp’s perspective, a second stripper is a loose cannon.

    If the would-be perp is thoughtful, sober and planning ahead.

    Comment by mythago — May 5, 2006 @ 1:32 am | Reply

  62. “You say you’re sure. What is your certainty based on?”

    Common sense.

    Comment by wumhenry — May 5, 2006 @ 11:45 am | Reply

  63. “I think test studies, done on college students, have shown that witnesses can pick the wrong person out of a line-up even if the right person is standing right there.”

    If there’s a published study that reports that test subjects frequently picked the wrong person out of a line-up that included the right person AND said that they were completely certain about the identification, I’d love to see it.

    Comment by wumhenry — May 5, 2006 @ 11:50 am | Reply

  64. “if you put 42 photos of young white male jocks side by side, including different photos of Seligman and Finnerty, and told me to pick out those two gentlemen and no others, I don’t know if I’d be able to.”

    I don’t think you’d have any problem with it. The human brain is hard-wired for face recognition.

    And how likely is it that you’d wrongly identify another member of the team as Finnerty or Seligman yet be 100% certain you got it right? About the same as a snowball’s chance in Hell.

    Comment by wumhenry — May 5, 2006 @ 12:00 pm | Reply

  65. Wumhenry, it’s a plain fact that people who make police IDs sometimes ARE very sure about it – sure enough to testify under oath, at trial, that the ID is definite. And they are sometimes wrong. Your supposition that such mistakes would be impossible if the real criminal is in the line up is, as far as I can tell, entirely without support.

    You’re also ignorant of how little “certainty” means. The ID process can create certainty; a witness looks at a photo again and again, and in his or her mind travels from “this face looks familiar, I think” to “the more I look at this, the more I stare at this face and try to recall being attacked, the more they seem linked” to “I’m certain this is the right face.” The process does not require deliberate dishonesty or malice; it’s just the ordinary way we can fool ourselves because we want to help the DA, and we want to believe that the people who attacked us have been caught and will be tried.

    Nothing I’ve said above is at all controversial; all of it is supported by research.

    At this point, you’re simply refusing to acknowledge facts, in favor of your Archie-Bunker style “common sense.” You don’t have a single logical argument in favor of your view; you don’t have any evidence; you just have a totally unjustified certainty that whatever you say must be correct. Until such a time as you can provide some evidence or logic to support your views – something you seem reluctant to do – I’m done debating you. You may have the last word.

    Comment by Ampersand — May 5, 2006 @ 12:24 pm | Reply

  66. “it’s a plain fact that people who make police IDs sometimes ARE very sure about it – sure enough to testify under oath, at trial, that the ID is definite. And they are sometimes wrong.”

    As I’ve said before, I don’t doubt that people sometimes finger the wrong person from a lineup. But that doesn’t quite go to the point. The question here, as I have repeatedly reminded you, is: how likely is it that a genuine rape victim would finger the wrong person out of a lineup that includes the actual perp and yet be 100% certain that she has correctly identified the guilty one? You say that I’ve got no evidence, but then, neither do you. You haven’t alleged that you’re aware of any study that found that people frequently identify the wrong person with absolute certainty under such circumstances. In the absence of
    “scientific” evidence I’m content to rely on common sense — though perhaps that’s taking unfair advantage in a debate with you. 😉

    Comment by wumhenry — May 5, 2006 @ 3:27 pm | Reply

  67. i have a doubt sir, why does blood tranfusions doesnot produce allergy even though wbc containd dna.. i had heared that no dna is alike.then there is a chance for allergy know?

    Comment by ashokamahadev — June 4, 2016 @ 10:26 am | Reply

  68. How often do they find the rapist because of a sperm sample? Is it likely that they will find the individual who raped someone based off of the sperm or does that individual have to already be in the system or something?

    Comment by utopia — August 27, 2016 @ 7:54 pm | Reply

  69. my question is this ? If evidence found is consistent with type-o the victim and the accused is A-negative how could you convict?

    Comment by Bruce smith — December 7, 2016 @ 2:59 pm | Reply


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