Sunday, January 25, 2009

DNA Preservation

The Denver Post reports this week that state prosecutors support a bill to "fix" a requirement imposed last year to preserve DNA evidence associated with crimes. This "fix" needs a close look.

The Innocence Project of Florida has taken note and offers the following commentary:

An article in the Denver Post today details a move by the District Attorney to limit the rules requiring the preservation of DNA evidence.They are now, they say, "too sweeping to be practical," a charge which I find hard to believe. I would imagine that, were a police officer to err on either side, they would choose to err on the side of having too much evidence.

House Bill 1121 would change the law so authorities have to preserve DNA evidence only in the case of felonies or sexual-assault cases and only when that evidence could be relevant to a disputed issue in the case.The bill does, however, leave some checks in place, such as...requiring a hearing before discarding evidence and requiring evidence in murder and rape cases to be stored for the life of the defendant. Judicial oversight before the destruction of evidence is an important, yet necessary, inclusion in the bill. (That is, I can't imagine the police being granted the authority to destroy evidence on their own.)

As for the list of crimes with which the bill is concerned, I find it lacking. Rapes and murders will almost always have biological evidence involved, but a list that contains just those two crimes is far from comprehensive. Any crime in which the perpetrator leaves biological evidence that could be tested to reveal their identity is a case in which that evidence should be preserved. It's conceivable, for example, that DNA could be an issue in assaults, robberies, burglaries, and other crimes as well. Ted Tow, executive director of the Colorado District Attorney's Council, furnished an example of when it would be "impractical" to retain DNA evidence from a crime:

"There's a bar fight with 27 witnesses. It's not a whodunit," Tow said. "Pretty much anything anybody comes into contact with" is being stored under the current legislation.

This might seem like a good point, but it's a bit of a straw man. Every chair, railing and table that gets touched might not need to be preserved, but certainly the broken glass bottle wielded as a weapon, or the bloodstained shirt of the victim. Those seem like awfully probative pieces of evidence. Keep in mind, if the DA had their way, they would retain none of this evidence, since a bar fight is not a rape or a murder. The fact that there are 27 witnesses makes this hypothetical a bit amusing, but we should remember that witness testimony has certainly proven to be problematic before.

What happens when there's only 3 witnesses, or as many as 9 witnesses, as in the case of Troy Davis in Georgia, in which seven of the nine eyewitnesses recanted after the fact?

DNA is a powerful scientific tool used both to convict and exculpate suspects. Its importance and probative value can hardly be understated, but we hamstring ourselves as a society if we begin destroying biological evidence before it is

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