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Archive for the ‘dna’


State v. DNA profile 1

Posted on January 26, 2010 by Gideon

In these days of DNA, scientific and forensic evidence, it was bound to happen. As this very interesting (and lengthy) opinion from the California Supreme Court details, a “John Doe” warrant issued mere days before the statute of limitations was set to expire, identifying the defendant only by his DNA profile, satisfies the “particularity” requirement of the Fourth Amendment.

The DNA was taken from a crime scene (and victim) in 1994 and after the issuance of the warrant, a cold hit matched the profile to that of the defendant. Only problem is, the DNA taken from the defendant was in violation of then-existing CA law.

The defendant raised several challenges to the warrant: that since the DNA was taken in violation of the law, it was in violation of the 4th Amendment; that this triggered the exclusionary rule; and that the warrant was not specific enough because it was issued in the name of “John Doe”.

You can image the usual responses to such claims. The court relies on the abomination that is Virginia v. Moore to dispense with the first argument: that just because state law prohibits something, doesn’t mean it is a violation of the Fourth Amendment. The second is dealt with by regurgitating the very narrow reading of the exclusionary rule (and the third argument was just plain silly to begin with).

This shouldn’t be a problem anymore for most states, since the statute of limitations for all sex crimes is now one googol years (an actual number). But the case is a curious oddity nonetheless and it is my solemn sworn duty to bring this to your attention.

QED

NAS: Bullshit! 4

Posted on February 19, 2009 by Gideon

The NAS just called “bullshit” on many of the forensic techniques used in labs across the country, ranging from fingerprint, blood splatter, hair, arson and fiber analysis to bullet comparisons. The only technique escaping this harsh critique is DNA analysis, which has been the subject of voluminous study and testing.

The report [executive summary] finds fault with almost all aspects of forensic science: from the lack of standards and scientific scrutiny of “accepted” techniques like bitemarks to a lack of any uniform certification standards.

As a result, there has been little rigorous research to investigate how accurately and reliably many forensic science disciplines can do what they purport to be able to do.  In terms of a scientific basis, the disciplines based on biological or chemical analysis, such as toxicology and fiber analysis, generally hold an edge over fields based on subjective interpretation by experts, such as fingerprint and toolmark analysis.  And there are variations within the latter group; for example, there is more available research and protocols for fingerprint analysis than for bitemarks.

Lawyers can and have gone to town questioning experts on the “reliability” and “scrutiny” of their methods, but this report provides another powerful tool in exposing (in some instances) the pure speculation of this type of expert evidence:

The report points out the critical need to standardize and clarify the terms used by forensic science experts who testify in court about the results of investigations.  The words commonly used — such as “match,” “consistent with,” and “cannot be excluded as the source of” — are not well-defined or used consistently, despite the great impact they have on how juries and judges perceive evidence.

In addition, any testimony stemming from forensic science laboratory reports must clearly describe the limits of the analysis; currently, failure to acknowledge uncertainty in findings is common.  The simple reality is that interpretation of forensic evidence is not infallible — quite the contrary, said the committee.  Exonerations from DNA testing have shown the potential danger of giving undue weight to evidence and testimony derived from imperfect testing and analysis.

The recommendation is not to “junk” all this science, but rather to develop it and to acknowledge and admit its limitations:

Margaret Berger, a professor at Brooklyn Law School and a member of the panel, explained: “We’re not saying all these disciplines are useless. We’re saying there is a lot of work that needs to be done.”

Said U.S. Court of Appeals Judge Harry Edwards, co-chairman of the panel: “There are a lot of people who are concerned, and they should be concerned. Forensic science is the handmaiden of the legal system. . . . If you claim to be science, you ought to put yourself to the test.”

For more reading, go here, here and here. Scott has his take here.

If only they’d used such caution the first time 5

Posted on January 04, 2009 by Gideon

As often happens, I lollygag when it comes to writing posts. Then, all of a sudden, in a span of a day of day or two, several stories appear that tie together the strands in my head. Today is such a day.

Percolating in the back of my head was some chagrin directed toward the prosecutors in the Clarence Elkins case (aka #92), the subject of Friday night’s Dateline. Elkins, in a case with some parallels to Miguel Roman, was convicted of raping his niece and raping and murdering his mother-in-law based on one single dubious eyewitness: his niece, who told cops that the killer looked like her uncle. Clarence, meanwhile had an alibi: he had been drinking heavily at a bar and then came home to his wife, who was awake. They went for a walk.

The police, however, got their blinders on because of the statement of the niece, despite the fact that rudimentary DNA testing excluded Elkins. Elkins’ wife, convinced of his innocence, began investigating on her own:

DNA Exoneration FTW 0

Posted on December 19, 2008 by Gideon

Following up on the DNA exoneration story from two weeks ago, I can happily point you to this report that Miguel Roman has been granted a new trial and was released from custody today, in time for the holidays.

Judge David P. Gold agreed after a brief hearing today to release Roman, 52, on a promise to appear in court. Roman’s lawyers, citing evidence that appears to exonerate Roman in the 1988 killing of 17-year-old Carmen Lopez, petitioned for a new trial for Roman.

Gold granted that motion today.

Prosecutor David Zagaja noted that the petition for a new trial stems from newly discovered evidence stemming from a technology that “simply didn’t exist” in 1988. It was not immediately clear whether the prosecution will proceed to a new trial or move for a dismissal of the case.

It would be remarkable if the State decided to prosecute him again, so  I don’t think that will happen. More likely than not, the charges will be dismissed.

The saddest part of this story is the 20 years of his life that Roman lost.

Close to another DNA exoneration 9

Posted on December 06, 2008 by Gideon

The Great State of Seacrest Connecticut might be close to its second DNA exoneration ever. (You know, it’s strange how these things play out. A few weeks ago I remarked to someone that I hadn’t heard anything about the Innocence Project lately and I wondered if they were working on anything.)

Nearly 30 years ago, three women either disappeared or were found murdered. One person linked all three investigations: Pedro Miranda. The police could never get enough to charge him and eventually another man – Miguel Roman – was convicted of the murder of one of them and sentenced to 60 years in prison.

DNA: Something new and something old 5

Posted on July 21, 2008 by Gideon
DNA

DNA helix

The biggest story of this past weekend is this L.A. Times piece on the accuracy of the DNA identifications and the statistics used to come up with the probabilities of a random match. Much has been said in the blawgosphere (all of it worth reading) by the Greenfield, the Underdog Mark Katz, the public defender dude and an engrossing lesson in statistics by the Windypundit. They’ve done a wonderful job, so I won’t dwell on it much.

The gist is this: A DNA “match” is when the two pieces of biological evidence share the same markers (loci) at 9 random locations (or 11 or 13 or 15…) The odds of that happening, the State usually contends, is one in 6 billion (and they use that number arbitrarily because it is the population of the world). So in essence, they argue that the only person in the world who could be the source of that piece of DNA is the defendant.

The problem should be evident. Of the millions and billions of loci in the human DNA, 9 or 11 or 15 is an infinitesimal fraction. So, it is possible that if we start looking for matches at 20 or 30 or 100 or 1000 loci, the probabilities will drop. Then we might be talking about 1 in 100,000 or 1 in 20,000. Not bad odds, given the populations of cities and countries.

Still, if these “Arizona searches” (as some are trying to call them in an effort to get the name to stick) haven’t reached your State yet, a number like 1 in 300 billion trillion gazillion quadrasesquecentenellian shouldn’t faze you.

DNA cannot tell a jury when it was deposited or whether the donor actually committed a crime during the deposit. This will not change, even if the odds that it was your guy that deposited the DNA get better.

Creative Commons License photo credit: beckita115

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