WEBSTER, N.Y. – An ex-con killed two firefighters with the same caliber and make military-style rifle used in the Connecticut school massacre after typing a note pledging to burn down his neighborhood and “do what I like doing best, killing people,” police said Tuesday as another body, believed to be the gunman’s missing sister, was found.

William Spengler, 62, who served 17 years in prison for manslaughter in the 1980 hammer slaying of his grandmother, set his house afire before dawn Christmas Eve before taking a revolver, a shotgun and a semiautomatic rifle to a sniper position outside, Police Chief Gerald Pickering said.

The death toll rose to three as police revealed that a body believed to be the killer’s 67-year-old sister, Cheryl Spengler, was found in his fire-ravaged home.