FBI’s feeble forensics

“Hundreds of defendants sitting in prisons nationwide have been convicted with the help of an FBI forensic tool that was discarded more than two years ago. But the FBI lab has yet to take steps to alert the affected defendants or courts, even as the window for appealing convictions is closing, a joint investigation by […]

“Hundreds of defendants sitting in prisons nationwide have been convicted with the help of an FBI forensic tool that was discarded more than two years ago. But the FBI lab has yet to take steps to alert the affected defendants or courts, even as the window for appealing convictions is closing, a joint investigation by The Washington Post and ’60 Minutes’ has found.” The bureau has now agreed to release the files involved (John Solomon, “FBI’s Forensic Test Full of Holes”, Washington Post, Nov. 18; more Post coverage; Obbie, Nov. 18; Ambrogi, Nov. 19; Althouse).

5 Comments

  • One has to be careful when Barry Scheck is involved in a matter.

    In general nearby samples of material will have similar characteristics. One may recall that there was a statistically significant correlation between draft number and date from the first draft lottery that resulted from the way that dates were added to the mixing bowl putting nearby dates together.

    As I understand it, one can not say that a box of ammunition has a unique chemical signature. Remember when DNA was first being used, million to one odds were challenged by saying that there were seven people in new York city with the same DNA profile. Although that argument was moronic, the forensic community honed there tests to get astronomical odds. Don’t forget that NAS had to take back it’s position in how the DNA odds are calculated. Scheck and Neufeld tried many times to get the NAS letter into the OJ trial.

    Although the 60 Minutes and other reports state firmly the the lead analysis was just mumble jumble, no data was presented to support the claim itself.

    What drives me up the wall is that Scheck makes use of the definitiveness of DNA results in his innocence project and discredited DNA results in the OJ trial. I despise the guy.

  • If I had been made aware of this technology at any time I would have thought it bogus.

    Bullets are cast in presumably large batches, probably much larger than a retail box, and then they’re dumped into a hopper and assembled with the rest of the round and placed in boxes arbitrarily. A box of ammo probably shares a melt with the previous and/or following box, although some boxes might include bullets from two melts since the manufacturer has no reason to avoid this. The box in question and its meltmates would be assembled into cartons and shipped to a retailer. The retailer would sell different boxes from the same batch to different people who live and shoot in the same region.

    So if I shoot half the bullets in my box at a target but I live and buy my ammo in an area where someone got shot, the shooter might have bought the next box of ammo from the same dealer and left metal with the same chemical signature in the victom. The police can later “match” the rest of my box of ammo with the victom’s bullet.

    -dk

  • This would have to depend on what specifications the manufacturer has for the alloy used in the bullets. If you have a precise specification and it is strictly adhered to then all of that manufacturer’s bullets should be nearly identical. If there isn’t a strict specification then bullets in the same melt may not be identical, it would depend on the order that each bullet’s material left the crucible when it was cast.

  • The FBI’s own internal study in 1991 should have relegated this forensic “tool” to the junk science bin. If they were able to find two bullets manufactured 15 months apart that matched, and two from the same box that didn’t, what else could one conclude about the value of this type of analysis?

    Forensic procedures that are passed off to juries as “scientific proof” really bother me. A local mailman here in AZ (Ray Krone), was convicted of murder, not once but twice, after a state bite mark “expert” wowed the jury with dental impressions,CAT scans and his “expert opinion” that proved the defendant was the attacker. Krone was only freed (10 yrs. later)after DNA positively linked the crime to another suspect (who happened to be serving a sentence for child molestation).

  • Mr. Nuesslein, in fairness to Mr. Scheck, he did not claim DNA matching was junk science during the OJ murder trial. He claimed that Mr. Furman [the policeman who obtained the blood samples] did not follow standard rules that would have prevented anyone from using the blood to contaminate other pieces of evidence, thus leaving a reasonable doubt as to whether Mr. Furman might have tried to frame OJ. This is in fact a serious issue, and is is why testimony as to Mr. Furman’s racist statements was relevant.

    I’ve occasionally quipped that the LA police are so incompetent that they couldn’t even frame a guilty suspect.

    -dk