Current Gunshot Residue Forensics are Rubbish
November 26, 2005
11:31 a.m., MT

So says a recent New Scientist opinion piece titled Why we cannot rely on firearm forensics. Selected excerpts from the interesting article (why it's labeled "opinion" is a curiosity):

[A] New Scientist investigation has found that someone who has never fired a gun could be contaminated by someone who has, and that different criminal investigators use contradictory standards. What's more, particles that are supposedly unique to GSR can be produced in other ways. ....

"None of what we do can establish if anybody discharged a firearm," says Ronald Singer, former president of the American Academy of Forensic Sciences and chief criminalist at the Tarrant county medical examiner's office in Fort Worth, Texas.

Peter De Forest of John Jay College of Criminal Justice in New York goes further. "I don't think it's a very valuable technique to begin with. It's great chemistry. It's great microscopy. The question is, how did [the particle] get there?" ....

But recent studies have shown that a non-shooter can become contaminated without going near a firearm. Lubor Fojtásek and Tomás Kmjec at the Institute of Criminalistics in Prague, Czech Republic, fired test shots in a closed room and attempted to recover particles 2 metres away from the shooter. They detected "unique" particles up to 8 minutes after a shot was fired, suggesting that someone entering the scene after a shooting could have more particles on them than a shooter who runs away immediately (Forensic Science International, vol 153, p 132). [Link added by me -- goes to abstract]

A separate study reported in 2000 by Debra Kowal and Steven Dowell at the Los Angeles county coroner's department reported that it was also possible to be contaminated by police vehicles. ....

[I]t is possible to pick up a so-called "unique" particle from an entirely different source. Industrial tools and fireworks are both capable of producing particles with a similar composition to GSR. And several studies have suggested that car mechanics are particularly at risk of being falsely accused, because some brake linings contain heavy metals and can form GSR-like particles at the temperatures reached during braking. ....

Singer maintains that the technique is useful if used carefully. "I think it's important as part of the investigative phase," he says, though not necessarily to be presented in court.

Yes, you read that right. Singer says that GSR forensics cannot establish if a person fired a gun, but the varied techniques are still "useful". What I want to know is, for what? Oh, wait -- I know what it's useful for. [Snake issues angry hiss]

Sunni

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