The .38-caliber gun that killed Phillip Peatross couldn't have gone off accidentally, according to a senior firearm analyst who testified on Tuesday. Someone had to pull the trigger. The big question at the center or this case is who was it: Peatross or his girlfriend at the time, Caryn Kelley?
Kelley is on trial for manslaughter and faces up to 30 years in prison.
Read more: Caryn Kelley "anxious" to testify
A senior crime lab analyst also testified on Tuesday that both Peatross and Kelley tested positive for gunshot residue, but he couldn't identify which one actually pulled the trigger. He was only able to determine that both were within close proximity of the gun when it was fired.
Kelley became emotional as prosecutors showed photos from the crime scene: blood splatter on Peatross' clothing, his personal belongings, bottles of alcohol in the kitchen and garage, the bloody bed where Peatross' body was found, and Peatross' dead body.
She seemed to perk up when her ex-husband took the stand. He testified that the couple, married for 13 years, took gun training at a range. He kept a .38 revolver in the house, either in a lockbox or in a nightstand.
Read more: The Caryn Kelley trial: Who's who?
Prosecutors say Kelley has changed her story several times, claiming that she fired the gun in self-defense and alleging that Peatross shot himself.
But Kelley's defense attorney says Peatross had left the house after a night of drinking and arguing. When he returned, Kelley grabbed the gun, thinking he was an intruder. He entered her bedroom and tried to take the gun, saying he was going to hurt himself. That's when Kelley's lawyer says the gun went off. Peatross died from a single gunshot wound to the head.
Kelley's defense lawyer says her client is anxious to tell jurors her side of the events. She may take the stand this week.
With reporting by In Session's John Alleva.
Stay with HLNtv.com for complete coverage of Kelley's trial.