Man pulls trigger to prove gun is empty, gun fires and kills woman standing on other side of wall

21-year-old Cornelius DeJong of Redmond, Washington was at a party at a friend's house. He brought his .40-caliber semi-automatic handgun with him to the gathering. DeJong has a concealed weapons permit for the gun. According to police documents, several people handled the gun over the course of the evening and it eventually ended up placed in a bedroom under a mattress.
Around 3 o'clock in the morning DeJong went to get the gun when another person in the room "objected to the handgun being handled while the subjects were under the influence of intoxicating liquor." DeJong then removed the magazine from the gun and pulled back on the slide. To show the gun was empty he pointed the gun at the wall and pulled the trigger.
Unfortunately, there was bullet in the chamber and the gun fired. The bullet went through the wall and struck 20-year-old Claire Thompson who was standing on the other side of the wall. Claire was struck in the neck. She was rushed to the hospital but died of her injuries later that morning.
DeJong pleaded not guilty to charges of first-degree manslaughter. According to a police spokesperson, "We do believe that it was due to reckless handing of the gun that caused it to go off. We do not believe it was premeditated."
Documents indicate that DeJong had been drinking before the incident.