WEBSTER, N.Y. — It was a simple call to put out a car fire, the sort of routine job that firefighters tackle all the time. The fire truck hurtled to the assignment early Monday in this drowsy town on the shores of Lake Ontario that was preparing for the joys of Christmas.

But it apparently was a trap, the authorities said. There were a house and a car burning. There was also a waiting killer, who had stationed himself like a sniper on a berm above the firefighters.

Before they could begin to extinguish the fire, the firefighters were met by a burst of gunfire. Four were hit by the volley of bullets, and two died. An off-duty police officer from nearby Greece, N.Y., who was on his way to work, was wounded when he and his car were hit by shrapnel.

For a few hours, the scene was chaotic: flames ignited adjacent houses as the police frantically searched for the gunman. They would find him dead near the beach, with a self-inflicted gunshot wound to the head. He was identified as William Spengler, 62, a man who had served time in prison and who lived in the burning house. In 1981, he pleaded guilty to manslaughter for bludgeoning his 92-year-old grandmother to death with a hammer. He was imprisoned until 1998.