Washington, Dec 26 (IANS/EFE): The New York man who killed two volunteer firefighters and wounded two before taking his own life left behind a note suggesting he planned more deaths, police said Tuesday.

"I still have to get ready to see how much of the neighborhood I can burn down and do what I like doing best, killing people," William Spengler, 62, said in the typewritten note.

The ex-convict set a house on fire early Monday in Webster, New York, a suburb of Rochester, and then lay in wait to ambush the firefighters who came to put out the blaze.

Webster police chief Gerald Pickering read excerpts from Spengler's note at a press conference.

Human remains were found amid the charred remains of the house the perpetrator shared with his sister, 67-year-old Cheryl Spengler, the police chief said.

The shooter's sibling is missing and authorities suspect the remains are hers, Pickering told reporters.

William Spengler, who served 17 years behind bars for the 1981 beating death of his 92-year-old grandmother, was armed with a revolver, a shotgun, a Bushmaster rifle - the same weapon used in the Newtown school massacre - and an "arsenal of ammunition", the police chief said.

Spengler began shooting at the firefighters before they could even get out of the truck, Pickering said.

Reacting to the Dec 14 bloodbath in Newtown, Connecticut, President Barack Obama has pledged to work for a ban on the sale of assault weapons and extra-large ammunition clips.