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New York man who attacked firefighters killed himself

The gunman who lured two firefighters to their deaths died of a self-inflicted shot to the head and wasn’t hit by return fire from a police officer, New York State Police said Thursday.

But investigators still hadn’t made a positive identification of the body found in William Spengler’s burned house. They have said they believe the remains are those of his sister Cheryl Spengler, 67, who also lived in the house near Rochester.

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Autopsies showed that West Webster volunteer firefighter Michael Chiapperini died of a single gunshot and Tomasz Kaczowka was killed by two, police said.

Spengler set a car on fire and touched off an ‘‘inferno’’ in his Webster home on land along the Lake Ontario shore, took up a sniper’s position, and opened fire on the first firefighters to arrive at about 5:30 a.m. Christmas Eve, authorities said. He wounded two other firefighters and an off-duty police officer who was on his way to work.

A Webster police officer who had accompanied the firefighters shot back at Spengler with a rifle in a brief exchange of gunfire before the gunman killed himself.

Trooper Mark O’Donnell said investigators weren’t releasing information about how Spengler got the military-style Bushmaster .223-caliber semiautomatic rifle, 12-gauge shotgun, and .38-caliber revolver found with his body. He said they are still tracing the history of the guns. Spengler spent 17 years in prison for killing his grandmother in 1980 and was barred from possessing weapons as a convicted felon.

Police have said they believe Spengler used the rifle to attack the firefighters because of the distances involved. The rifle, which had a combat-style flash suppressor, is similar to the one used by the gunman who massacred 20 children and six women in a Newtown, Conn., elementary school earlier this month.

The Spengler siblings had lived in the home with their mother, Arline Spengler, who died in October. In all, seven houses were destroyed by the fire.

Investigators found a rambling, typed letter laying out Spengler’s intention to destroy his neighborhood and ‘‘do what I like doing best, killing people.’’

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