Devondre Davis was 16 when he was shot in the head in a Tacoma apartment then dumped into a garbage bin.
Pierce County prosecutors say Davis death in September 2011 was cold-blooded murder.
Defense attorneys call it a tragic accident.
The man who pulled the trigger, either on purpose or inadvertently, went on trial this morning in Superior Court.
Anthony Clark, 21, is charged with first-degree murder, first-degree robbery, unlawful possession of a controlled substance with intent to deliver and unlawful possession of a firearm.