Police say Spengler, who was convicted of manslaughter in 1980 in the death of his grandmother, set fire to a car and house to lure firefighters to his home on the shore of Lake Ontario. Officials said Spengler was released from prison in 1998 and on parole until 2006.
"Obviously this is an individual who has a lot of problems," said Webster Police Chief Gerald Pickering.
Pickering said Spengler died of a self-inflicted gunshot wound to the head.
Asked about the guns used in the incident, Pickering said he was not clear which weapons, or how many, had been used by Spengler.
"Spengler was a convicted felon so he's not allowed to possess weapons," said Pickering. "I don't know where those weapons came from but we're certainly going to find out."
Officials said seven homes have been destroyed by the fire.
Pickering also said that Spengler's sister is believed to have been living in the home with him, and that she is thus far unaccounted for.