NEW FAIRFIELD, Conn. (AP) — A Connecticut man fatally shot a masked teenager in self-defense during what appeared to be an attempted burglary early Thursday morning, then discovered that he had killed his son, state police said.

State police identified the youth as 15-year-old Tyler Giuliano, who was shot at about 1 a.m. outside a neighbor's house in New Fairfield, which is along the New York line just north of Danbury.

A woman who was alone in the home believed someone was breaking in and called the teen's father, who lives next door, state police said. The father grabbed a gun and went outside to investigate, troopers said.

The father confronted a person wearing a black ski mask and black clothing, then fired his gun when the person came at him with a shiny object in his hand, police said.

When police arrived, they said the father was sitting on the grass next to the woman's home and Giuliano was lying in the driveway with gunshot injuries. The teen was pronounced dead at the scene.

"All in all it's a tragedy," said Lt. J. Paul Vance, a state police spokesman.

The father, Jeffrey Giuliano, is a fifth-grade teacher in town. A message seeking comment was left for him Thursday.

Tyler was a student at New Fairfield High School.

The News-Times of Danbury reported that Superintendent of Schools Alicia Roy sent parents an email Thursday afternoon about what happened.

"Our district has experienced a tragedy that has affected us deeply," she wrote, adding that students weren't told of the killing because all the facts weren't clear.

No charges have been filed. State police are investigating.

An autopsy on the boy is planned.

Copyright 2012 The Associated Press.