WEBSTER, N.Y. — A teenage boy convicted of setting a fire that killed his adoptive father and two brothers inside their western New York home was sentenced Wednesday to 15 years to life in prison.

Sixteen-year-old Michael Pilato didn't comment at his sentencing in Monroe County Court in Rochester, local media outlets reported.

Pilato was convicted last month of second-degree murder, attempted murder, murder by arson and arson. Police said he poured gasoline throughout his Webster home and set it ablaze early on Dec. 7, 2011, killing his 71-year-old father, Carmen, and two brothers, 16-year-old Peter and 12-year-old Josh.

Pilato's mother and 13-year-old sister were injured.

A defense lawyer argued Pilato was experiencing "extreme emotional disturbance" when he set the fire.

Pilato's mother, Elaine Pilato, supported him throughout the trial and says he didn't set the fire on purpose. She has previously said she plans to appeal his conviction.

Michael Pilato, who was 15 when he set the blaze, was one of several children Carmen Pilato adopted after his biological children were grown.

Michael Pilato described a chaotic home life, disputes with his parents over his use and sale of marijuana, and anger upon learning he'd been adopted, according to witnesses who talked to Pilato after his arrest and testified at his trial.

Webster police said they had been called to the Pilato residence several times in the year before the killings to investigate "missing-person situations," but officials didn't elaborate because the complaints involved minors.