This first episode of the Case Studies mini-season of the Just Science podcast series of the Forensic Technology Center of Excellence is an interview with Michael Fagert, a certified latent print examiner of the Kansas Bureau of Investigation, who discusses a latent print phenomenon that is not often seen in casework.
There are few instances of identifiable fingerprints on cartridge cases recovered from crime scenes, since the firing process introduces adverse physical and thermal stressors to fingerprint residues. Several processing methodologies have been investigated for the development of latent prints on spent ammunition, such as gun blue solutions, but only a few studies have reported success on casework samples. Michael Fagert discusses his published case report on how an untreated latent print encountered on a cartridge case was subsequently identified to the suspect in the case. Officers responded to the scene of a homicide, where witnesses reported they heard some gunshots and then observed a man leaving the scene in a black hoodie and black pants. While officers were holding the crime scene, they noticed an individual at a nearby residence who matched this description, and they took him into custody for further investigation. In processing the crime scene, crime scene technicians collected four cartridge cases, with one being near the victim’s body, one near the door to the victim’s residence, one near the driveway and one near a nearby street. This evidence was collected and brought back to the lab and submitted for examination. The crime-scene photographs of the cartridges were examined, and one appeared to have a print impression. The evidence was requested and obtained from the firearms section of the lab. Although the cartridge had been swabbed, the print was still visible. Without the excellent photograph that captured the print, it might have been missed. The procedure that yielded the most informative information from the print is described. The FTIR analysis provided the most informative result. Narrowing the print to the individual held at the crime scene is explained, along with how the print could be traced to the person who fired the gun.