Paul and Mary Alice Young had purchased a gun for protection, it had remained unused until 2004 when Mary Alice went into her hallway closet and took the small silver revolver out of a shoe box. She shot her self in the head. Later in season 1 their son Zach finds the gun who is horrified that Paul had kept it
11 years later, at Bree Van de Kamp's house, Zach dressed as a flower delivery man arrives and places the gun under a pillow while everybody is in the kitchen. Paul's wife Beth Young finds the revolver and the she thinks that the ladies are trying to frame her. When the police show Paul Young the gun he is shocked, and knows that his son had placed it.
The revolver is seen in a number of flashbacks over the seasons.