The field of firearms identification is not reliable enough to allow expert testimony linking crime scene bullets to specific guns, Maryland’s top court ruled this week. [More]
Watch the Democrats jump on this to push serialized ammo.
[Via Michael G]
This is something that the courts, and defense attorneys, have known about for years, much to the chagrin of the FBI’s Lab. Ballistics evidence is very similar to what is called ‘tool-mark’ evidence, both operating on the premise that one surface interacting with another surface causes distinct markings that cross-transfer between each surface–such as a pry-bar interacting with a door-frame, or a fired bullet interacting with a rifled barrel interior. Each surface ends up with ‘tool marks’ to one degree or another.
The problem with BOTH is that an examiner of either has to make a subjective decision as to whether the correlating marks are ‘the same’–relying upon training and experience, but not necessarily precise, accurate standards and actual science. This ‘opinion’ can only determine ‘class characteristics’ as generalities.
With bullets, as in this case, an examiner can determine that a bullet was fired from, say, a Glock 17 barrel with the old polygonal ‘rifling,’ which is great–but he can’t determine if said bullet was fired from a SPECIFIC Glock 17 out of millions, only that the ‘class characteristics’ of the marks on the fired bullet are ‘consistent’ with having come from A Glock 17, without excluding all other possible 17s.
It’s the same with chambered and/or fired cartridge cases and their surfaces, too, and guns with ‘standard’ rifling; An examiner can establish the possibility that a certain gun brand, model, and caliber was used, but cannot exclude all other guns of the same type to a scientific certainty.
Although the FBI and other police labs would like the courts to believe that ‘tool marks’ and ‘class characteristics’ evidence are akin to fingerprints (which are ALSO not infallible) and DNA, they simply aren’t.
Since when has testimony had to be accurate– or even true?
I wonder how many sociopathic killers will now qualify for new trials with the evidence that sealed their convictions now inadmissible…?
Taser “ammo” is serialized. Wonder what real-world results it has to show?