SAN DIEGO (AP) — A man has been sentenced for shooting a 16-year-old boy to death 20 years ago on a Southern California freeway.

Phong Huynh was sentenced Friday to 50 years to life in prison. It was his second sentence. His first conviction was overturned in 2017.

Prosecutors say in 2000, Huynh followed and opened fire on Nghia Tan Pham, who was driving on Interstate 15 in San Diego. Pham was shot in the head.

Authorities say the attack was retaliation for a pool hall fight in which Pham was involved.

The case went unsolved until 2012, when the driver of the car in which Huynh was a passenger stepped forward.

Huynh — then living in Montana — was arrested. His conviction was later overturned but he was convicted again earlier this year.