The Salt Lake County Sheriff’s Office has arrested an 18-year-old man who is accused of fatally shooting a friend in the back.

The victim was dead from a gunshot wound in his upper torso when police arrived on the scene shortly after 1 a.m. on Saturday, according to a probable cause statement. Police have identified the victim as Roman Karpunin, 16.

The suspect told police he accidentally shot his friend while mimicking a police officer. He said he pulled the trigger while pretending to arrest his friend. He said he thought the gun was on safety and unloaded because he had taken the magazine out.

The suspect smoked marijuana before the shooting, according to police.