Fingerprints & DNA on Cartridges & Cartridge Cases

Via following a Sitemeter referral (someone at the FBI was looking for answers and ended up on my blog) I discovered The California Criminalistics Institute did a study on obtaining forensic evidence from cartridge casings before and after firing. The conclusions were:

Likelihood of obtaining useable fingerprints on c. cases:

Not likely.

If you eliminate bloody prints from consideration, then only 3/32 [9%] cartridge cases displayed useable prints.

No useable prints were obtained on the cartridge cases that had been fired.

If you eliminate bloody prints from consideration, then no DNA profiles were obtained.

I’m not sure that it’s of any use to me but I found it fascinating.

10 thoughts on “Fingerprints & DNA on Cartridges & Cartridge Cases

  1. Just once…. just once I would love to see CSI (the tv show) say, “We lifted some prints off the bullet shell casings… but yeah, they were useless.”

  2. More and more television shows have been making “this isn’t CSI”-type comments, but, sadly, whiz-bang magic still makes for good television. It is interesting that fired cartridges are useless for fingerprints, though – I guess the short-term heat and pressure destroys the oils.

  3. I seem to remember reading an article describing a new technology for lifting prints involving electrically heating the cases up to flash evaporate the oils and whatnot and leaving the salts behind, which then were used for printing. Anyone else remember seeing that?

  4. ubu52,

    I hadn’t heard about that technology. That is very interesting.

    My first impression is that it wouldn’t be practical. It would seem to me that each box of ammo would have to have a different tag which makes it a manufacturing nightmare. Plus if someone shoots 10s of thousands of rounds each year they will have their clothes and equipment contaminated with hundreds if not thousands of different tags. Perhaps just being next to someone at the range could contaminate you with someone else’s tags.

    The tags also it increases the chances of someone getting framed. The bad guy steals a few rounds of ammo from your box while you are shooting at the range and commits a crime with them. Now you are in jeopardy.

    Think the problem through and I think you will find there are a lot of problems to be solved.

  5. I think there are a lot of problems with it, which might be why the articles are a year old and we aren’t hearing anything about this being used.

    http://news.softpedia.com/news/Making-Tags-for-Bullets-out-of-Pollen-91332.shtml

    http://www.sciam.com/blog/60-second-science/post.cfm?id=nano-coated-bullets-could-help-solv-2008-08-04

    The second article mentions this: “In addition to the coating, the researchers are also experimenting with bullet casings made with a micro-patterned pyramid texture able to retain dead skin cells–and with it, DNA evidence–from a thumb as it loads a cartridge into a firearm.”

    You know, just thinking about all the technology that has come to be in the last 30 years (DNA, computers, etc.), I don’t doubt they’ll find a way to do this in the next 20 years.

  6. “…casings made with a micro-patterned pyramid texture able to retain dead skin cells…”

    Pretty easy to defeat that, to say nothing of the fact that revolvers retain spent cases until they’re manually ejected. For that matter, I and others often use a brass catcher on semi autos at the range so we don’t have to hunt for cases in the snow, grass, etc. Then there’s the ten shot fotee foe (nine from the cylinder plus one 20 gauge shot load) Lemat revolver, which uses no cases at all.

  7. Well, obviously we need more law and government intrusion into our lives. That will solve the problem for sure.

    Disclaimer for the impaired: I jest.

    Simplistic (or complicated) engineering regulations usually have engineering overrides (often trivial).

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