New Haven — A popular fifth-grade teacher will not face prosecution for fatally shooting a knife-wielding prowler in a ski mask who turned out to be his 15-year-old son.

A prosecutor released his findings Friday that no criminal charges will be filed against Jeffrey Giuliano (joo-lee-AH'-no), saying the use of force was justified.

State police have said Giuliano went outside with a gun around 1 a.m. on Sept. 27, 2012, when his sister called to say someone was trying to break into her house next door. Authorities say Giuliano saw a masked person holding a knife come toward him in a threatening manner and shot him.

He later was told the person was his son Tyler, who died of multiple gunshot wounds.