Letter From High-Ranking FBI Lawyer Tells Prosecutors How To Avoid Court Scrutiny Of Firearms Analysis Junk Science

from the cheating-to-win-is-how-the-FBI-defines-'justice' dept

Law enforcement — including the FBI — like to claim they’re heavily invested in science. The use of forensic “science” has been with us for years, but nowhere is it more sketchy than in law enforcement labs, where zero accountability rubs elbows with zero outside review of methods.

For years now, evidence historically claimed to be almost certain indications of guilt has been shown to be, in many cases, no better than a coin flip. Even DNA has its problems, especially when “expert” witnesses overstate their ability to exclude “innocent” DNA from cluttered crime scenes. The unwillingness of police to police themselves has been aggravated by the unwillingness of courts to question statements made by forensic techs — ones that include things like claiming a person can be positively identified by the wrinkles and creases in their mass-produced clothing.

One judge — Jed S. Rakoff — did speak up. He excused himself from the DOJ’s examination of law enforcement forensics once it became clear the Justice Department was more interested in finding supporting claims than dissenting voices. The DOJ’s Deputy Attorney General informed Judge Rakoff that examination of pre-trial evidence procedures was beyond the “scope” of the Commission, resulting in Rakoff’s resignation.

Blood pattern analysis, bite mark patterns, hair matching, etc. Nearly every supposedly inarguable form of forensic evidence has been determined to be junk science under closer examination. Even the FBI has admitted its forensic experts have routinely overstated the certainty of their findings during sworn testimony.

You would think all of this would add up to a major overhaul of forensic procedures and requirements that testing methods be subjected to peer review or blind testing or literally anything other than the zero scrutiny it has enjoyed for years. You’d be wrong. Instead, law enforcement officers and officials have been putting their energy into finding ways to keep their junk science from being rejected by courts.

A letter obtained by The Daily Beast shows the FBI would rather lie to courts than give up the use of yet another questionable forensic technique: bullet matching. Investigators claim bullet fragments contain unique markings from the barrel of the gun they’re fired from and these can be used to uniquely identify the weapon used to fire the bullet. This, of course, assumes there are no similarities between mass-produced weapons and mass-produced bullets that might result in “matches” that say nothing more than a certain kind of gun fired a bullet designed to be fired from that model of gun.

This supposed form of evidence was called into question by the Obama Administration:

The most damning criticism of the field came in a 2016 report by the President’s Council of Advisers on Science and Technology, or PCAST, which found that “firearms analysis currently falls short of the criteria for foundational validity,” and that the studies the field’s practitioners often cite to support their work are poorly designed and “seriously underestimate the false positive rate.”

Following this report, some judges began to push back against this questionable evidence. Law enforcement is pushing back, led by none other than a high-ranking lawyer representing the FBI’s forensic team.

Late last year, a forensic firearms analyst in Wisconsin emailed a remarkable document to more than 200 of her colleagues across the country. It was a handout from an online lecture given by Jim Agar, the assistant general counsel for the FBI Crime Lab.


In the two-page handout, Agar instructs firearms analysts on how to circumvent judges’ restrictions on unscientific testimony. He even suggests dialogue for prosecutors and analysts to recite if challenged. Most controversially, Agar advises analysts to tell judges that any effort to restrict their testimony to claims backed by scientific research is tantamount to asking them to commit perjury.

The letter [PDF] is quite the read. The FBI lawyer refuses to even consider the idea that bullet-matching forensics might be faulty. Instead, he instructs prosecutors and expert witnesses to work together to undermine any attempt the court (or defense lawyers) might make to depict these findings as questionable. It starts by implying courts are wrong to even question the expertise of forensic techs.

So far, no court has excluded the testimony of a firearms identification expert witness. The greater likelihood is that the court will attempt to compromise and craft some kind of language that weakens or neuters the expert’s identification opinion, substituting that terminology for the examiner’s identification opinion. Some courts have put in place so-called “limitations” to that testimony, which fundamentally alter the examiner’s opinion. However, these are not true limitations because they make material and substantive changes to the expert’s testimony. These are wholesale attempts to rewrite the firearm expert’s testimony by a layman with no experience in forensic science. This practice is not supported by either science or the law.

And it wraps up by suggesting forensic experts opt out of testifying completely rather than have their expertise and statements called into question:

If the court insists on limiting the firearms expert testimony to GRC or class characteristics, I probably would not call the examiner at all. Instead, I would put on a lay witness such as the case agent or an armorer for the police department to testify about the similar class characteristics of the weapon and the bullets and/or cartridge cases.

Does this sound like science to you? Anything backed by actual science would be able to survive evidentiary challenges. Since this isn’t, it’s not strong enough to even survive cursory examination. Any case relying solely on this junk science should be doomed. But by forcing the court to play by the FBI’s terms (or, conversely, preventing the forensic expert from being questioned), the agency can still roll the dice on bypassing scrutiny of its means and methods.

The problem for the FBI now is that this letter is out there in the public domain. Judges paying attention to these issues will know exactly why the prosecution is asking leading questions of its forensic expert or why there’s no forensic expert being asked to testify. This letter alone should cause most firearms analysis to be tossed immediately. It probably won’t, but it should, unless the law enforcement agency can definitively show it uses methods not used by the FBI or has completely disregarded the suggestions of the FBI’s counsel.

Real evidence should be able to survive scrutiny. It should be able to stand on its own without the prosecution playing “hide the witness.” This letter is a tacit admission that firearms analysis is more guesswork than science. As such, it should be considered damning evidence of its own — something that will force law enforcement experts to thoroughly and scientifically justify their assertions. And it should definitely encourage the DOJ to consider halting the use of firearms forensics until it can find a scientifically sound way of doing so. But, if history is any indicator, the DOJ would rather score cheap wins that use forensic evidence backed by sound science.

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Comments on “Letter From High-Ranking FBI Lawyer Tells Prosecutors How To Avoid Court Scrutiny Of Firearms Analysis Junk Science”

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anon says:

why should judges care?

The people who should really care are defense attorneys and their clients. If the only reason that their client(s) are in jail is a lie told by (an) FBI witness(es), then they have excellent cases for requests for new trials at the very least, or like in Massachusetts, after the conviction of the drug lab employee, the release of all of the wrongly convicted people (and probably some who were guilty, but thats what MA gets for breaking the law themselves.)
I dislike people who commit crimes, but to have those people working in charge of our law enforcement agencies makes me want to puke.

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That One Guy (profile) says:

'Our science is so amazing we don't dare bring it to court.'

If your ‘science’ is so weak that even you know it can’t stand up to scrutiny to the point that you’ll pull an ‘expert witness’ rather than have their claims examined it’s not science, it’s handwaving rubbish and deserves to be treated as such.

Most controversially, Agar advises analysts to tell judges that any effort to restrict their testimony to claims backed by scientific research is tantamount to asking them to commit perjury.

That is an incredibly damning tactic there, and should be enough to toss any testimony they might want to present as grossly unreliable. Telling an ‘expert’ that the only evidence they’re allowed to present is that which has been shown to be scientifically sound in no way is forcing them to commit perjury, and if anything is preventing them from committing perjury, so that objection is telling in all the wrong ways of what they were going to do.

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mechtheist (profile) says:

This is really and truly horrific. How man thousands of innocent folks have been convicted by bogus evidence? This is an incredibly wide ranging conspiracy to commit heinous crimes. It’s hardly a stretch to accuse them of kidnapping and murder. They should use the typical drug-war crazed conspiracy tactics to go after all of these criminals masquerading as officers of the law and US Prosecutors etc. That would be an incredibly entertaining spectacle.

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IndefinitelyTired says:


Hi, I’m hella lonely and bored rn, and I was wondering if anyone wanted to talk, whether it be about Science or Politics or Literature; really, I’d be open to engaging in a conversation about anything. Also, some help with my Algebra 2 class would be nice, I truly don’t understand much. As of now, we are working on logarithms. Makes me wanna commit end(funct), if you catch my drift.
Anyhoo, I would love to talk. About anything.

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Bobvious says:

Re: Re: hi

Well, logarithms is an anagram of algorithms. And the Al Gore Rhythms might keep you entertained, https://www.youtube.com/watch?v=1AQQoVC7pXk

If you’re going to be doing anything with decibels then you’ll find logarithms very handy. Maybe this will help with the discussion on relevance or motivation, https://math.stackexchange.com/questions/16342/what-is-the-point-of-logarithms-how-are-they-used

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TKnarr (profile) says:

The FBI’s suggested tactics can easily backfire on them. Defense attorneys who know about them can put their own experts on the stand who’ll willingly limit their testimony to what’s backed up by scientific research which will gut the evidence the FBI wants left unquestioned. That leaves the FBI with a bunch of unpalatable choices: keep their own experts away and face a big credibility gap, put their experts on and try to explain why their experts insist on testifying to things they can’t back up, or try to discredit the defense’s experts and in the process discredit their own evidence.

reticulator (profile) says:

Re: expert witnesses for the defense

For the government, the cost of expert witnesses is chump change.

The government can throw multiple types of expert witnesses at the defense, still for chump change.

And that’s for expert witnesses who will testify that their fellow prosecution expert witnesses have wonderful track records over years of experience.

For the defendant who isn’t rolling in cash, not so much.

That Anonymous Coward (profile) says:

"is tantamount to asking them to commit perjury"
Unlike allowing them to testify which is perjury.

I’m sorry it makes you all unhappy but you’ve used this junk science to put people away rather than actual investigation to support the cases so you sort of deserve to have all of the cases reviewed & paying out a lot of money for people serving time over bite marks & other questionable bullshit you made sound like cutting edge perfect technology.

Protecting their image leads them to lie about "science" undermining the image they are trying to protect.
And still can’t figure out why people have growing concerns that the system is not fair or just.

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madasahatter (profile) says:


Forensics is excellent at ruling out potential suspects; think of it as an enhanced alibi. Depending on the specific evidence, often it cannot definitively prove a suspect is guilty. It often is inconclusive. As an example it is know the perpetrator has O negative blood. Anyone who has a different blood has an ironclad alibi; wrong blood type. Anyone who loosely matches the description of the perpetrator with this blood type could be the perpetrator but its inconclusive if they are.

Also, a solid case at trial does not rely on a couple of bits of forensic evidence if the DA wants a solid case. It should rely on several lines of forensic evidence that as it excludes others and only leaves the accused as the logical perpetrator. Some of the forensic evidence will be stronger, some weaker.

The problem is the tendency for the DA’s office and their ‘experts’ to push the evidence beyond what it is capable of showing. And then essentially lying to the jury about quality of the evidence. This particularly true if there is limited evidence.

Anonymous Coward says:

Re: Forensics

Bullet matching has got to be the worst for this. If a bullets rifling marks match a suspected weapon all you know is that the bullet was fired by any number of makes and models of firearm that use that same rifling pattern. Millions of possible matches.

If it doesn’t match though, you have definitely excluded the gun in question from having fired the bullet.

cattress (profile) says:

Cop killer

I wonder if detectives and prosecutors would feel at ease using their junk science to determine who to prosecute if the killer was targeting law enforcement and their families specifically? They might not care if they let the real killer walk when the victim is just a stranger, maybe even not a very sympathetic victim. But if the war on cops was actually real, and happening in a very personal fashion, I wonder if they would feel motivated to actually do their jobs right, or just bet on the likelihood that lots of arrests and convictions surely means they had to have gotten the bad guy.

That One Guy (profile) says:

Re: Cop killer

But if the war on cops was actually real, and happening in a very personal fashion, I wonder if they would feel motivated to actually do their jobs right, or just bet on the likelihood that lots of arrests and convictions surely means they had to have gotten the bad guy.

The former would require doing their jobs and acting professionally, the latter allows them to act like thugs to a lot of people indiscriminately.

Not a hard guess as to which they’d prefer to go with.

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