Aaron Saucedo

PHOENIX — Phoenix police have arrested a suspect in a cold-case killing after linking a gun he allegedly owned to the crime scene.

Police say 23-year-old Aaron Saucedo is suspected of killing a 61-year-old man at an apartment complex on August 16, 2015.

Police say in a probable cause statement that detectives collected shell casings from the shooting and did an analysis that revealed they could have come from only one type of handgun.

Authorities allege that Saucedo sold the gun at a pawn shop. Detectives traced it to the new owner, who agreed to let them run tests.

Police say Saucedo knew the victim and that the gun used in the killing belonged to him.

He told police he didn't commit the crime when he was arrested on Wednesday.

There were no witnesses to the shooting.