Order of Processing Firearms

[L.J.Steele]

In a discussion of a case, an expert has testified that firearms should be processed for fingerprints before being test-fired for ballistics and that this examiner was able to lift prints from firearms in 10-12% of his cases.

Processing for prints before test-firing seems pretty fundamental -- handling the firearm to fire it would tend to smudge any prints on the grips or trigger, possibly on other working parts depending on what else the lab does in test firing.

But I recalled reading that bits of unburnt powder in the barrel can cause non-matching striae. I was wondering if fingerprint powder would cause a non-matching striae if it gets into the barrel or is it too soft/fine. I was also wondering about the effect of superglue fuiming on those particles in the barrel. Any thoughts?

[Charles Parker]

Ms Steele, there is what I believe a good article on processing firearms by Clive Barnum and Darrell R. Klasey from ATF. It is in Vol. 42 #2 (Mar/Apr 97) issue of the Journal of Forensic Identification. Of 1,000 firearms examined they were able to obtain 114 identifiable latent prints on 93 firearms.

I also have in my library two published studies done with CA Fuming on firearms. One study was to determine if Superglue is affecting the striation markings on test bullets from a weapon after it has been CA Fumed. The second one explored the possibility of a change in the weight of trigger pull after CA Fuming. In both studies CA Fuming had no effect on the results of the firearms tested.

I am trying to put my fingers on those other two studies but I pulled them recently for another person and they are now buried in my refile stack, but I wll find them.

The first one I mentioned from Barnum and Klasey I believe I already have it converted to Word. If you want a copy, just let me know.

I have had Firearms Examiners complain about CA Fuming causing striations to be light on test firings, but then I ask them have they ever test fired a weapon that had light striations with the questioned but the weapon had not been Superglued-----Their response is yes. My next question is how can they tell it was the superglue that caused it since that can also happen to non CA Fumed weapons? I will not go into their response.

I have not known black fingerprint powder to affect a firearm. It is generally softer material than even unburned or charred gun powder.

However at my agency ever since they were able to obtain DNA from a checkered grip of a co-defendant who denied knowledge of the firearm our protocol goes like this. Most firearms are First--Swabbed for DNA, Second----Processed for Latent Prints, Third----Going to the Firearms Section for function and firing tests.

Hope this helps you (stay in Mass.)
Just a funny, I do not really mean it. (NOT)

Since everybody else is putting little sayings at the end of their posts here is mine.

FATE FAVORS THE PREPARED MIND.

[Steve Skowron]

Lisa, put a cork in it.. the barrel I mean. We were asked years ago by our firearms people if we would cork the end of the barrel before doing any powdering. They were more concerned about the mess than about anything else.

DISCLAIMER: The "put cork in it" comment was in jest. No attempt to be rude, childish, or otherwise insensitive was intended. No corks were injured in this posting.

[Cork Activist]

Good that no corks were harmed, but be aware that we are watching every word on this forum.

[Heidi Fraser]

I second the cork thing.... the suggestion, not the insult. While I tend to agree that the CA would not make a noticeable difference, it makes our firearms examiners nervous so as a courtesy to them, we plug up the barrels of all our firearms when we CA them. We use test firing earplugs. They're soft, foamy, and squish well even into the smallest bore barrels.

[G. Frog]

It would appear by inserting a cork or ear plug you may be transfering some trace material(s) into the barrel which could become an issue during the judicial process. CA nor powder has any effect on the lands and groves and if I am not mistaken, ask your firearms examiners if they don't clean the barrel prior to test firing. Of course any trace evidence is collected prior to this. I would suggest you re-read Mr Parkers response.

[Heidi Fraser]

Yes, just as you said. Trace collection would be done before latents processing or test firing. We have never had an issue with trace amounts of ear plug being in the barrel. The firearms examiners will, of course, clean the barrel if they have a problem with its state when they receive it. But they still prefer not to have CA in there, if possible.

[Cindy Homer]

Hi Lisa,

It was great to finally meet you in Burlington. Just wanted to add my two-cents (or less, depending on the quality you put in my response).

When I interned in the firearms section of another lab (before taking this position), I once watched the firearms examiner run a steel brush down the barrel of a firearm to clean it out after it had been in a sewer for a while. I watched, absolutely horrified. He was unrelenting and was actually able to still make the ID. I looked at it and, not being a firearms examiner myself, was still able to see all of the striations lining up, etc. Any firearms examiner I have spoken with since responds the same way I did when I saw him ram that brush down the barrel. But, needless to say, I still saw everything line up (but I am not a trained firearms examiner). I'm not sure what this says or what could be implied by this.

We dont get many usable prints off of firearms, they are a bear. The different firearms examiners we have here all have different opinions as to how they want the firearm processed. Some want tape over the open ends, some want only powder and some say it doesnt matter. I've chemically processed firearms, dousing the external areas with liquid and allowing it to dry. They dont care.

As far as order of processing, the firearm goes to trace, then we always swab rough areas first (like the checkered areas of the grip), process for prints and forward to firearms.

Hope you're well!
Cindy Homer

[G.Frog]

"watched the firearms examiner run a steel brush down the barrel of a firearm"

Are you sure it was a steel brush? That doesn't seem right. What would be the purpose of such?

[Cindy Homer]

I know it seems crazy but that's exactly what he did and I am certain it was a steel brush because I was like "Holy s%*#! What are you doing!!!???" The purpose? To him it was to clean out the debris in the barrel as a result of being in a sewer.

[G. Frog]

If it were to clean out sewage debris it seems a swab or gun cleaning patch would have been sufficient. Sometimes we are our own worst enemy.

[Shaheen]

Hello,

I ran "firearm" in my database of fingerprint papers, and this is what I came up with:

Templin, R. H. and Nielson, J. P. (1988) Evaluation of the effects of cyanoacrylate processing on pistol and revolver trigger pull Journal of Forensic Identification, 38, 161-164. [this tells you that there was no effect on trigger pull weight with CA fuming]

Onstwedder III, J. and Gamboe Jr., T. E. (1989) Small particle reagent: developing latent prints on water-soaked firearms and effect on firearms analysis Journal of Forensic Sciences, 34, 321-327. [this has something about CA fuming as well]

Freeman, H. N. (1999) Magnetic fingerprint powder on firearms and metal cartridges Journal of Forensic Identification, 49, 479-484.

Barnum, C. A. and Klasey, D. R. (1997) Factors affecting the recovery of latent prints on firearms Journal of Forensic Identification, 47, 141-149. [This previously mentioned]

I hope this helps,
Shaheen

[L.J.Steele]

I know it seems crazy but that's exactly what he did and I am certain it was a steel brush because I was like "Holy s%*#! What are you doing!!!???" The purpose? To him it was to clean out the debris in the barrel as a result of being in a sewer.

At a wild-assed guess, the barrel may have picked up a fair amount of surface rust from being in water for a while. If the firearm was fired before it got dumped in the sewer, he may have had worries about the rust mucking up the straie.)

I tend to use brass bore brushes for cleaning my own gear, esp the single-action stuff that uses round nosed lead ammo, tho I have seen steel bore brushes (made of a milder grade steel than typical bore metals.) I would have thought labs would be using ultrasonic cleaners -- I'm told they are fast, thorough, and no abrasion to the barrel or breech face.

[G. Frog]

Lisa as to your wild guess: Once the weapon is removed from it may develop a light coasting of rust as you describe. Then contrary to popular belief that the barrel will immediately become pitted and deteriated is myth. How long does it take a metal item to oxidize, pitted, non functional? It is not over night and requires time. This is also dependent on the finish or metal the weapon is made of. This light coating is one of the reasons why the barrel may be cleaned using a clean patch after it is examined and processed for fingerprints, trace evidence to include DNA, tissue etc. The barrel is also examined for any obstructions. Before test firing the weapon is function tested to include trigger pull. Your cleaning with the brass or copper brush is mainly to remove powder particles after you have fired the weapon. Cleaning the weapon prior to test firing has no effect on the lands and groves.

We have conducted experiments with hand guns in water from ocean, canal, lake, tap and swimming pools and left the weapons up to 45 days under water and were able to recover controlled latent fingerprint evidence as well as no adverse effect on the weapon to include lands and groves. Ph factors as well as water temperatures were also recorded.


The weapons tested were revolvers and semi automatic pistols including stainless steel, parkerization, blue, teflon.

We have also recovered long guns from brackish water in a mangrove swamp which had been submerged for up to two weeks in an actual case and there were no adverse effects to the weaspon or lands and groves and identifiable latent prints were also recovered.

[L.J.Steele]

Once the weapon is removed from it may develop a light coasting of rust as you describe. Then contrary to popular belief that the barrel will immediately become pitted and deteriated is myth.

I'm not sure how much rust it takes to change the individual characteristics (straie) on a firearm. Certainly it would take some serious damage to mess up the class characteristics (straie from lands and grooves). Some of the firearms treatises talk about what I think of as "transient" straie being created by powder grains or bits of lead -- that's not a lot of material.

It gets more complex. According to Biasotti, A Statistical Study of the Individual Characteristics of Fired Bullets, 4:1 J. Forensic Sci. 34, 34-50 (1959), Biasotti frequently encountered 15-20% matching striations on land or groove impressions between similar types of bullets known to be fired from different firearms of the same manufacturer and type. The percentage of matching striations in bullets fired known to be fired from the same firearm was 21-38%. I'd assume the remaining striations were those "transient" marks which can change between firing. (Any firearms guys or gals here with more up-to-date figures than Biasotti?) It doesn't seem like it would take a lot of surface rust to risk masking or damaging those individual marks.

Your cleaning with the brass or copper brush is mainly to remove powder particles after you have fired the weapon. [\quote]

Mostly powder, soot, and for the unjacketed ammo, lead build-up, yup. Over time firing and cleaning affect the individual straie -- you'd have to do something pretty drastic to mess up the rifling itself.

We have conducted experiments with hand guns in water from ocean, canal, lake, tap and swimming pools and left the weapons up to 45 days under water and were able to recover controlled latent fingerprint evidence as well as no adverse effect on the weapon to include lands and groves. Ph factors as well as water temperatures were also recorded.[\quote]

Please write this up for JFI or one of the other periodicals! I had one examiner in CT (major city police department which shall remain otherwise nameless) testify that he didn't bother to print the outside of a car involved in a robbery/homicide because it had rained and there wouldn't be any prints. <sigh> (Yes, I know that's not true, but as appellate counsel all I can do is drop a footnote about sloppy crime scene work -- trial counsel didn't catch it at the time.) Please, publish this stuff in hopes that folks will take prints of the once-wet stuff! (Yes, it may create damming evidence against my clients -- OTOH, it may exculpate a few and help bring in the real bad guys.)