‘Ballistic Fingerprint’ Database Expands Amid Questions About Its Precision

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At the Portland Police Bureau's North Precinct, Officer Jason Hubert is getting ready to fire a confiscated handgun into a thick metal bullet trap filled a thick sludge called snake oil.

He's about to enter a bullet casing into the National Integrated Ballistics Information Network (NIBIN), a nationwide database of high resolution images of shell casings managed by the Bureau of Alcohol, Tobacco, Firearms and Explosives. The NIBIN terminals and data are new investigative tools for hundreds of local police departments, allowing them to match markings on shell casings with casings found at other crime scenes, and sometimes with guns.

Hubert dons his bullet proof vest, eye and ear protection, and checks the weapon to make sure it works properly. After warning the precinct over a PA system of the test fire, a colleague holds out a net to catch the shell casings.

After conducting the test fire, Hubert places the casings under a microscope to choose which one is the best candidate to be imaged. In a dark room, hunched over a microscope, he explains he's looking for the best ejector mark. That's the mark left on the casing as it's expelled from the gun.

"The ejector mark is the fingerprint of the shell casing," says Hubert.

Until this year, the Portland Police would have to send these casings to a crime lab and results would take months to get back. But now investigators are getting results in a matter of hours instead of months. And instead of just being a resource for prosecutors at trial, the NIBIN "match" is being used by investigators to generate leads, despite uncertainty about the precision of the match.

"Ballistic fingerprint" not necessarily unique

NIBIN was started in 1999 and has primarily been used by forensics examiners to testify at trial about the likelihood that a bullet was fired from a particular gun. But that's all changing now. The Department of Justice is allocating money and resources to put NIBIN terminals into the hands of local police departments.

Assistant U.S. Attorney for the District of Oregon Suzanne Hayden helped get the NIBIN system into police departments so they could be used in local investigations.

"Each firearm that shoots a bullet leaves an imprint that's unique to that firearm," she says.

But some defense attorneys challenge the notion that the markings are unique, and the FBI says even expert testimony can't make that claim with certainty.

Janis Puracal is an attorney and the founder of the Oregon-based nonprofit Forensics Justice Project.

"The problem is no one's gone out and actually determined that it could only be matched to that gun to the exclusion of all other guns in the universe," says Puracal, who helps defense attorneys challenge forensic evidence that isn't supported by science. She points out that flawed firearms forensics have led to exonerations in the past.

In 2013 a Mississippi man's life was spared hours before his scheduled execution after the FBI said experts had overstated the science. In a note sent to the district attorney in that case, the bureau clarified that "the science regarding firearms examinations does not permit examiner testimony that a specific gun fired a specific bullet to the exclusion of all other guns in the world."

Claims of certainty, the letter said, "are not supported by scientific standards."

Puracal says using NIBIN as an investigative tool is less problematic than using it in court, but she still takes issue with its use.

That's because a NIBIN match, she says, can lead to cognitive bias in the investigators — a kind of tunnel vision.

"It's the idea that once we start building that narrative and it starts making sense the more things we see that fit into that same narrative," she explains.

Despite these reservations, almost 200 local law enforcement agencies own NIBIN terminals and are using the data as an investigative tool.

Moving cases forward

On a recent night in Portland, Sgt. Steven Wilbon has his eye on a car parked down the street from Jefferson High School. He pulls up and talks to the three people inside about the homecoming game that's just getting out. After a short conversation Sgt. Wilbon tells them to be good and drives off. As he leaves he runs their plates.

A sound effect comes back from the computer; Wilbon says it means the car is stolen. He turns around to go back, calling for backup. Officers approach the car from both sides, telling the people inside to keep their hands visible.

Wilbon said they found three loaded guns in the car. No one had the required conceal-carry permits, and the people in the car had outstanding warrants.

In the past the investigation may have ended with three people arrested and the guns placed in an evidence locker. But, because the Portland police have this new equipment, the casings were immediately entered into NIBIN. And because the Seattle police also use NIBIN, the ATF database indicated a match to shootings in Seattle.

A police department spokesperson in Seattle says it was a lead that moved their case forward — which is exactly how the Department of Justice intends for it to be used.

This story comes to us from Guns & America, a public media reporting project on the role of guns in American life.

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