An 18-year-old man has been charged for fatally shooting his teenage friend in the back in an incident he says was an accident.

Kaden Christiansen was charged Wednesday with a second-degree felony for manslaughter and third-degree felonies for obstructing justice and purchasing a weapon despite being a restricted person.

An officer went to a house in Kearns on Saturday after a report that someone had been shot, according to charging documents. The officer found Roman Karpunin, 16, on the kitchen floor with a wound in his chest. Karpunin was declared dead after emergency medical personnel arrived.

Christiansen originally told officers that an unknown person in a black hoodie shot Karpunin before running away. He later admitted that he shot Karpunin. He told the police that they had been pretending to be police officers and he shot Karpunin without realizing the gun would actually fire.

Christiansen, Karpunin and several other people —including Christiansen’s girlfriend and Karpunin’s brother — were at the house at the time of the shooting. Karpunin’s brother told officers that he was playing video games when the shooting happened. He said he didn’t hear an argument before the gunshot. Another witness told officers that Karpunin and Christiansen were in the kitchen together when the shooting happened. The witness said they had been “playing cops” earlier in the day.

Salt Lake County District Attorney Sim Gill asked for Christiansen to be detained without bail.