A convicted felon who set his house on fire and killed two firefighters and his sister in Webster, N.Y., on Monday before taking his own life left a note outlining his intention to set his neighborhood ablaze and "do what I like doing best, killing people."

READ MORE: Four Firefighters Shot While Responding To Rochester Blaze

Police say William Spengler, 62, shot at firefighters responding to the scene. Two other firefighters were wounded in the shootout. 

Police found a typed note at the scene, but have only released one line to the public.

From The Washington Post:

He [the police spokesperson] declined to reveal the note’s full content or say where it was found. He read only one chilling line: “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.” 

Police also found a body inside Spengler's burnt-down home, believed to be 67-year-old Cheryl Spengler, the killer's sister.

Previously, Spengler had served 17 years in prison for killing his grandmother. He was not allowed to own firearms.

READ MORE: Upstate N.Y. Gunman Killed Grandmother In 1980

Read the full story at The Washington Post.

Reach reporter Aaron Liu here.