In yet another blow to those who think CSI is real-life,

One of the interesting organizations out there is Jews for the Preservation of Firearms Ownership, JPFO for short. Being on their mailing list brings you some interesting things, like this link to an article at New Scientist titled Why we cannot rely on gunshot forensics.

The scene has been played out on lots of shows: someone suspected of a crime is tied to it by a finding of gunshot residue on their skin or clothing, and the day is saved. However:
"Now, 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."

Other ways, they say? Yeah, like laboratory contamination. Like walking into a room where a shot has been fired. Like sitting in a police car. Like working on machinery or fixing your brakes:
"...it 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."

Read the whole thing, as they say. And pay attention to the last paragraph:
"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. But he adds: "There are people who are going to be a bit more, shall we say, enthusiastic. That's where you're going to run into trouble."

You think maybe? Right now the Oklahoma City PD is going through a mess that started about a year ago when it was discovered that the one in charge of their crime lab had a reputation of , shall we say, 'getting the evidence an officer needed'. Which would be fine, except for the cases where it turned out the evidence wasn't really there. Several cases that ended in convictions have been thrown out, more are being reviewed and lives were ruined.

I cannot remember where I read it, but a year or two ago a study showed that an FBI lab specialty, 'proving' a bullet came from a particular box of ammo by the exact breakdown of the lead(bullets from the same lot would have the same composition, right?), was crap. It turned out that as an ingot of lead cools, and is later remelted, elements can shift around in the metal, causing a bullet to not resemble one from the same batch, or to resemble one from a whole different lot.

Which all means more to watch out for and wonder about when some crime lab expert tells us whodunnit.