William Spengler mugshot (credit: Monroe County Sheriff's Department)

WEBSTER, N.Y. (CBSNewYork/AP) — Police in Webster, N.Y., say the man who lured firefighters to their deaths in a blaze of gunfire left a typewritten note saying he wanted to burn down the neighborhood and “do what I like doing best, killing people.”

But officials said the note did not include a motive for Monday morning’s deadly assault.

Webster Police Chief Gerald Pickering said Tuesday 62-year-old ex-convict William Spengler armed himself with three weapons and set his house afire to lure first responders into a death trap.

“Spengler had armed himself heavily,” Pickering said.

Police also said they found human remains in Spengler’s home. They believe they are those of his missing 67-year-old sister, Cheryl. However a medical examiner needs to confirm the identity. A friend told the Associated Press Spengler hated his sister.

Spengler killed himself as seven houses burned around him Monday.

Firefighters Michael Chiapperini, left, and Tomas Kaczowska. (courtesy: WebsterPost.com/Messenger Post Media/Facebook)

Firefighters Michael Chiapperini, left, and Tomas Kaczowska. (courtesy: WebsterPost.com/Messenger Post Media/Facebook)

Spengler killed volunteer firefighter and police lieutenant Michael Chiapperini, 34, and firefighter Tomasz Kaczowska, 19. He wounded firefighters Joseph Hofsetter and Theodore Scardino, who were both hospitalized in serious condition.

Police said Spengler was using a Bushmaster .223-caliber rifle – the same gun as used by the gunman in the Newtown massacre. He was also armed with a .38 revolver and a shotgun.

Outside the fire station in Webster, flowers and candles are placed in memory of the murdered firefighters as residents in another town are gripped by tragedy, CBS 2′s Dick Brennan reported.

Pickering said Spengler “was equipped to go to war.”

Spengler previously served 17 years for manslaughter in the death of his grandmother. He was jailed until 1998, and on parole until 2006.