Loren Christopher Mertes, 20, pleaded not guilty Monday.
He is charged with first degree manslaughter after he reportedly shot and killed his friend on July 5.
Mertes is currently in custody at the King County Correctional Facility in Seattle.
His bail has been set at $300,000.
A case setting hearing has been scheduled for 1 p.m. Monday, Aug. 6 at the Regional Justice Center in Kent.
King County Sheriff’s Office deputies were called to Mertes residence in Covington where he rents a room.
When deputies arrived they were told that around 8:10 p.m. Mertes pulled the trigger on a loaded shotgun, shooting the victim in the chest, charging documents stated.
The two primary renters of the residence were in a different room when the shooting occurred and called 911.
Deputies entered the home to check on the victim and according to the charging documents, they overheard Mertes on the phone saying “I shot him, it was an accident.”
Once Mertes was detained and read his Miranda rights, he reportedly told deputies he had been manipulating the shotgun while hanging out with the victim and another person. He also told deputies he believed the gun was not loaded.
He continued, telling deputies that he had pulled the trigger three times and on the third time it unexpectedly went off.
The third person in the room at the time of the shooting told deputies that he was on his phone during the incident.
He said he heard the victim tell Mertes not to point the gun at people. He added, it sounded like Mertes was being careless with how he handled the gun, the documents stated.
The third person did not look up from his phone but told deputies he heard Mertes cock the gun and then heard it go off.
He told deputies he ran out of the room following the victim. The victim made it to the living room where he fell to the ground covered in blood, according to the charging documents.
The primary renters gave their statements to deputies and told them that at first they believed the noise was fireworks. Then they reported hearing Mertes yell “Oh my God, I just shot him, I didn’t know my gun was loaded.”
Another one of the primary renters told deputies that the day prior, July 4, she had heard that Mertes had loaded his shotgun and was intending to shoot it off in the yard.
According to charging documents, the residence is across the street from a busy strip mall in Covington.
Medics pronounced the victim dead at the scene.
According to the National Crime Information Center, Mertes has a 2016 conviction out of Oregon for disorderly conduct.
His Washington criminal history includes harassment in 2004, fourth degree assault in 2004 and a few juvenile misdemeanor convictions, according to the charging documents.