A Philadelphia teenager has pleaded guilty in the death of a police officer whose cruiser he struck with a stolen SUV in 2008.

Eighteen-year-old Andre Butler pleaded guilty to third-degree murder and other charges on Monday, the day his trial was scheduled to begin.

Police say Butler, then 16, was behind the wheel of a stolen Cadillac Escalade and leading police on a high-speed chase in September 2008 when the SUV crashed into a police car.

Forty-year-old Officer Isabel Nazario, who was in the cruiser's passenger seat, was killed instantly. Her partner was seriously injured.