Witnesses said De Jong had placed the gun in a safe at the house because he had planned to drink at the party, charging papers say. De Jong later removed the handgun from the safe when someone asked to see it.
Several people handled the weapon before it was placed under a mattress for safekeeping, charging papers say.
At some point, De Jong went into the room to retrieve the gun from beneath the mattress. The magazine was removed from the weapon and De Jong pointed the handgun at the wall and pulled the trigger to show the firearm was empty, the charging papers say.
"Unbeknown to him there was still a live round in the chamber of the firearm, and pulling the trigger had the effect of firing the projectile through a nearby wall," police wrote in their report.
The incident sounds eerily similar to the tragic case I mentioned yesterday, in which the shooter removed the magazine, but failed to realize there might still be a live round in the chamber, ultimately firing through both a wall and a young woman's head. Both shooters had permits to carry weapons, if not the proper training or common sense.