32% recovery rate of fingerprints from firearms

[arpratt]

Hi Everyone,

I provided negative testimony in terms of firearms in federal court yesterday. The defense counsel was very impressive and even referenced the Factors involving Recovery of Latents from Firearms article. During cross she asked me if I was familiar with the fact that Boston PD reported a 32% recovery rate in 2004. She did not give me an article for reference or any other information. I'm not familiar with this. Has anyone else heard of this?

[Gerald Clough]

He might have been off on the year. The lab suspended operations in 2004. That number turns up in a news story from 2007:

http://www.boston.com/news/globe/magazi ... thumbs_up/

Last year, her lab recovered prints on 32 percent of firearms involved in crimes, a quantum leap for the Boston unit. “Literally, we were at, like, 2 percent before,” says Suffolk County Assistant District Attorney Patrick Haggan.

[arpratt]

He might have been off on the year. The lab suspended operations in 2004. That number turns up in a news story from 2007:

http://www.boston.com/news/globe/magazi ... thumbs_up/

Last year, her lab recovered prints on 32 percent of firearms involved in crimes, a quantum leap for the Boston unit. “Literally, we were at, like, 2 percent before,” says Suffolk County Assistant District Attorney Patrick Haggan.

Hi Gerald,

Thanks. I found someone who knows Jennifer Hannaford. She confirmed that was their recovery and it has since fallen by 8-10%; however, the recovery doesn't only take into account identifiable latent prints. When we testify about recovery rate and the factors that affect it, we are strictly referring to identifiable latent prints. How are other agenices handling recovery rate? Is any ridge detail recovered from a firearm or strictly identifiable prints?

[Gerald Clough]

I think BATF reports about 10 percent recovery of identifiable prints. It's really hard to interpret plain rates. You don't know when an agency submits firearms. Do they submit them in apparent suicides? I think those often represent cases where the firearm is presumed to have been used immediately prior to discovery, normally without having been stored and transported and rolled around under car seats and where gloves are not the norm. And it doesn't take into account how vigorously they're treated, either because of processors' inclinations or the presence of equipment and supplies for different methods. Nor does it take into account any tendency for a lab to handle particular types of firearms. Property crime case may well have better maintained and therefore regularly cleaned and oiled guns that are more difficult to work with. "Street crimes" may well feature dry guns. Or how well field personnel handle and package firearms they will submit. And are they counting palms? Is ammunition counted among firearms? Still, it's clear that no one seems to be reporting a very high rate of success.

I note an FBI examiner testifying about lack of fingerprints on the M4 rifle the woman took from her interrogators. He cited the overall poor rate of recovery but didn't mention (at least not quoted in reports) that the standard military finish, Parkerized or similar, makes it especially hard. There are very few places, if any, on my M4 where I would expect to be able to place an easily recoverable print. Only one small area about the size of a finger pad that might take a good print on my Glock. Very little more on my mil-spec shotgun. None of them are in places where you'd likely press a finger.

And an interesting exclusion of experience-based testimony about the lack of fingerprints "on firearms and ammunition in the majority of criminal cases."
http://www.ndcalfpd.org/Briefbank/Exper ... 005%29.htm

So it might be nice to have Boston and BATF and whoever who's actually counted them to cite.

[arpratt]

I think BATF reports about 10 percent recovery of identifiable prints. It's really hard to interpret plain rates. You don't know when an agency submits firearms. Do they submit them in apparent suicides? I think those often represent cases where the firearm is presumed to have been used immediately prior to discovery, normally without having been stored and transported and rolled around under car seats and where gloves are not the norm. And it doesn't take into account how vigorously they're treated, either because of processors' inclinations or the presence of equipment and supplies for different methods. Nor does it take into account any tendency for a lab to handle particular types of firearms. Property crime case may well have better maintained and therefore regularly cleaned and oiled guns that are more difficult to work with. "Street crimes" may well feature dry guns. Or how well field personnel handle and package firearms they will submit. And are they counting palms? Is ammunition counted among firearms? Still, it's clear that no one seems to be reporting a very high rate of success.

I note an FBI examiner testifying about lack of fingerprints on the M4 rifle the woman took from her interrogators. He cited the overall poor rate of recovery but didn't mention (at least not quoted in reports) that the standard military finish, Parkerized or similar, makes it especially hard. There are very few places, if any, on my M4 where I would expect to be able to place an easily recoverable print. Only one small area about the size of a finger pad that might take a good print on my Glock. Very little more on my mil-spec shotgun. None of them are in places where you'd likely press a finger.

And an interesting exclusion of experience-based testimony about the lack of fingerprints "on firearms and ammunition in the majority of criminal cases."
http://www.ndcalfpd.org/Briefbank/Exper ... 005%29.htm

So it might be nice to have Boston and BATF and whoever who's actually counted them to cite.

Hi Gerald,

The BATF number you're referring to is from 1995. I work for BATF and we currently don't have a lab wide number for recovery but each individual examiner keeps their own stats. My is currently 13%. That percentage is identifiable latents recovered from firearms. The latents can be fingerprints or palm prints as long as their deemed identifiable. The recovery of latents from ammunition is kept as separate stats.

Thank you for the link. That's actually interesting and clever argument.

[Darrell Klasey]

I'm glad to see that my work still generates interest in the legal and forensic community. "Factors Affecting the Recovery of Latent Prints on Firearms" was reviewed in-house and peer reviewed by the JFI prior to being published in the March/April 1997 JFI. It has since been reprinted and referenced several times. You can refer to it as the Barnum/Klasey study, an ATF study, or a study by ATF examiners; your choice. The work was done from 1992 until 1995. Delays kept it from being published until 1997, three months after Clive Barnum passed away. 1,000 firearms were processed, generally using the same techniques (CAE fuming, R6G staining, ALS examination, as a minimum; black powder could be added at the end of the process, but never as the primary technique). And as examiner Pratt mentioned, we were looking for identifiable prints - no smudges, single ridges only, etc. Clive and I also didn't have the benefit of much in the way of image enhancement. So he took his numbers and guns and I took my numbers and guns and we came up with a success rate of about 10% for the 1,000 that we processed. I have always urged caution when providing numbers - if you process only two firearms and develop one identifiable print, technically you have a 50% recovery rate. In fact, with my current employer, I have a 0% rate, but I've only done 4 guns. But why did Clive and I report our numbers at all? We had been asked by a federal prosecutor if there was an "industry average" for prints on firearms. We couldn't find much published in the scientific literature, but everyone had a ballpark guess. So we looked at the work that we had already done, and reported what we had found. We couldn't have a control group, separating out time of recovery, temperature of recovery, etc., as the work was done before we got the idea to write the paper.

Clive and I had a few more controls in place for our next project, "Development and Enhancement of Latent Prints on Firearms by Vacuum and Atmospheric Cyanoacrylate Fuming," (JFI, Nov/Dec 2000), again published after his death, but one of the interesting things we noticed was that we still had about a 10% recovery rate.

So please, continue to use our work if you think it's valuable, remember to watch your numbers (total firearms processed) so that you have a sufficient base to draw conclusions from, and remember especially that our purpose was also to explain the factors involved in leaving/not leaving prints on firearms. Too many people try to use the 10% number on its own; that was only a part of our project. Maybe I'll have to do a talk at an IAI conference to explain some of this.

Darrell Klasey

[Gerald Clough]

And it's been pointed out to me that the document I pointed to is merely a motion, not an order or opinion.

[areitnau]

Hello everyone,

From 2005-2008 I was one of the Criminalists working for Jennifer at the Boston Police Department's Latent Print Unit. During that time, we did recover a high percentage of latents from firearms. The figure that has been reported in this thread (32%) was offered in a newspaper article, not a professional journal, as that figure was a unit statistic, not a scientific study.

We were often asked about these statistics, and the methodology used in our recovery methods. One thing that should be made clear was the Latent Print Unit, and the Boston Police Department went to great lengths to update the latent print processing equipment for the field personnel (Crime Scene Unit & Field Detectives), and performing a great deal of in-house training, to allow them to CA fume firearms in the field. This preliminary processing allowed firearms to be submitted to the laboratory after any latent print detail may have been developed and "locked" onto the surface of the firearm. We also noted a rise in the number of firearms that had latent detail revovered from them. As you may know, and citing the text of the ATF study, this preliminary processing reduced many of the factors that may affect the development and recovery of latent detail. Following the field CA fuming, lab personnel would follow up with further dye-staining methods and photography, if needed.

The high percentage of recovery that was cited previously may have been the statistics of latent recovery, but if memory serves, the percentage of latents of value, and even the percentage of firearms that had latents induvidualized to a person, were above 15%. While the personnel of the Latent Print Unit strove to conduct casework in a timely and efficient manner, one of the true contributing factors to the recovery rate was the initial firearm processing done prior to the evidence submittal to the laboratory.

I hope that helps explain things from our perspective a bit.

Andrew

[Kerrie]

Does anyone have statistics on swabbing firearms (particularly the trigger) for touch DNA prior to latent processing? We have swabbed the slide and grips before if it's a textured surface, but don't have stats on it.
Thanks!

[fingerprint]

Sometimes when I hear number like 32 percent i wonder a little bit about forms of measurements, especially when we see drop offs in the number in the following years. it is unfortunate that people need to doctor numbers from time to time. I have seen private investigators online say that they can actually pull fingerprints from all heavy metals at a sixty percent rate which is absurd to me. Have any of you seen the private investigator reviews on angies list?

[R. Gambler]

What was the recovery rate of fingerprints from firearms? Let’s see, is that recovery of visible ridges? Recovery of ridges with detail? Recovery of identifiable fingerprints? Recovery of latent fingerprints of value? Recovery of fingerprints from weapons that had been recently fired? Recovery from handguns? Recovery of fingerprints from weapons examined by crime scene personnel? Recovery of fingerprints from weapons examined by fingerprint experts? Recovery by personnel with access to a full range of processes? And what is the metric for "identifiable" or "of value"? And what does the recovery rate mean to a trier of fact? And what is the error rate of the process(es) used? Statistics are wonderful!