Source: Dave Bangert / @DaveBangert

DELPHI, Ind. — The unspent cartridge that helped police obtain a search warrant and the eventual arrest of Richard Allen is the subject of testimony Friday in Carroll County.

Richard Allen is charged with four counts in the 2017 murders of teenagers Abigail Williams and Liberty German. In the original charging documents, an unexpended 40-cal cartridge found near the bodies was traced to Allen’s gun.

During the morning session of the Delphi trial on day seven, the State of Indiana called witness Melissa Oberg. He works for a clinical asset health management company as an operational data analyst, but previously worked for the Indiana State Police as a forensic firearms examiner. She is the one responsible for testing Allen’s gun and confirming, in her opinion, that the round from the crime scene was put through Allen’s gun.

Oberg spent the morning session testifying, in granular detail, about the process in which he would test pistols, the structure of a gun and the structure of a cartridge. Oberg explained to the jury that a cartridge is a single unit of ammunition designed to go into a firearm. A cartridge has a case, primer, powder and bullet, which is the projectile.

Oberg was tasked with conducting a crime scene cartridge examiner and a brand new cartridge that goes through Allen’s gun.

“A tool mark is the characteristics imparted to an object by contact and extended force from a tool,” Oberg testified to the jury.

Oberg testified to two types of tool marks: imprinted and striated.

Some tool marks can be made before, during and/or after a cartridge is made, Oberg said.

Actual cartridge versus test cartridge

Oberg testified that the cartridge at the crime scene was in good condition, Winchester brand, cal. 40. cartridge. Oberg also noted that the cartridge was tested for DNA first and there was no biological substance on it. Law enforcement testimony over the past week has been consistent with Richard Allen’s DNA not being found at the crime scene.

Oberg testified that there were three possible ejector tracks: one in one direction and two in another.

Oberg testified that he tested a new cartridge using Allen’s gun.

Five images shown by Oberg show the tool markings “matched,” but she also testified that she fired the new cartridge while the crime scene cartridge was cycled.

Oberg argued in court that there is “research to back this up.”

Court is back in session and this article will be updated with more information as it becomes available from media pool reporters.