When there is a shooting, one of the most important pieces of evidence can be the shell casings that are left behind. When a round is fired from a semiautomatic firearm, the bullet itself is the projectile, while the shell casing is ejected and usually left on scene. Valuable evidence can be left behind on the casings, such as fingerprints and trace DNA. But the Pinellas County Sheriff’s Office (PCSO) can use yet another way to solve crimes using shell casings – the unique marks that each individual gun leaves on the rounds it fires. Just as we all have unique fingerprints that we leave behind, every gun leaves its own “fingerprints” in the form of mechanical marks left on both bullets and casings. While bullets might be too deformed from impact to clearly show marks, casings often retain clear imprints of the marks left by the firearm.
“NIBIN is the National Integrated Ballistic Information Network,” said NIBIN Administrator, Corporal Jeff Undestad. “It works with ATF to associate shell casings with specific firearms. My job is to identify crime guns through reports we receive and test fire them.” Not all guns meet NIBIN criteria for testing. Firearms collected through Risk Protection Orders and temporary injunctions aren’t tested. Nor are revolvers – which don’t generally leave a shell casing at the scene because the casings remain inside the cylinder unless the shooter reloads – and some older weapons. It is a myth that all guns are fired before sale to create a ballistics record.
When a firearm is recovered, after it is processed by forensics for DNA and fingerprints, Corporal Undestad checks it out of Property and Evidence and takes it for a test firing. Using standardized ammunition, he fires two rounds of ammo with brass primer, and two rounds of ammo with nickel primer to see which has the clearest marks. He’s found that nickel usually yields the best results. (Although the gun’s “fingerprint” doesn’t change, the clarity of the marks can vary from shot to shot, just as you may leave better or worse fingerprints depending on a variety of conditions.) Only the best of the four is entered into NIBIN.
Guns come to him in a variety of conditions. Many are dirty, some are damaged. Corporal Undestad has a lot of experience with firearms and the way they can malfunction, so he can usually convince them to fire, even if he has to do a single-round workaround. The worst firearms might have to go to the armorer to be checked before they can be fired.
The test casings are brought to the IBIS/Brasstrax machine, which uses 3D microscopy sensors to capture the topography of unique marks on shell casings or bullets. Corporal Undestad adjusts the lighting to reveal an extremely detailed view of the casing, and then marks sections of the image, such as the firing pin impression, to give the ATF Correlation Center the points of reference they need for their analysis. The image is then uploaded to the network to compare the marks against all others in the database. The system can link two shell casings from different crime scenes or link a shell casing to a particular gun. “The program ranks markings by similarity,” Corporal Undestad said, “but there is always a human eye reviewing it and making the final determination.”
Ballistic forensic information in NIBIN doesn’t directly identify the shooter, but it does provide links that serve as investigative leads for detectives to follow up on. “On my first day doing test fires, I had three leads.” PCSO has been doing this for two years, and offers it to other local agencies too. Before that, agencies had to send their firearms and casings to the Florida Department of Law Enforcement, a much more time-consuming process. “It’s a huge benefit for Pinellas County because now we have a much faster turnaround time, for us and all the detectives in Pinellas County.”
Corporal Undestad has a unique background that makes him ideal for the job as NIBIN Administrator. He was with the Largo Police Department for 33 years, and was their chief for the last 10 of those years. But for the first 10 years of his career he was an evidence technician. “I have a fondness for crime scene processing,” he said. “When I was with Largo I worked a lot with the PCSO Forensics team. They helped educate me on crime scene procedures. Now after retirement, I thought this was a perfect opportunity for me to get back into an area of law enforcement that I really loved when I was a new officer.”
Corporal Undestad has been enjoying his second career. “For me, it’s really rewarding. We’ve had cases match up with other agencies’ cases from years ago. They might be sitting on a cold case somewhere and suddenly we have a gun or a shell casing, and more information for them to follow up on.” Every recovered gun or shell casing is a new chance to solve a gun crime.
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