PORTLAND, Ore. (KOIN) — A 22-year-old man will serve up to 15 years in prison for his role in the death of Alexander Brodigan outside a Gresham school last year.

Brodigan was found shot to death outside the North Gresham Elementary School around 11:30 p.m. on June 19, 2017. Police said his car had crashed into the school, and his body was found inside the car.

Andrew McMahon, Austin Brown and 2 minor teens were initially arrested and charged with murder in the death. Later, a judge dismissed the murder charges against the minors.

Prosecutors had said the teens were part of a group that robbed and killed Brodigan, who had marijuana. The boy and girl had been about to enter their senior year in high school at the time of the killing.

McMahon pleaded guilty Thursday to manslaughter and attempted robbery, the Multnomah County District Attorney’s Office said. McMahon began serving a 5-year prison sentence for the robbery and will be sentenced at a later date for manslaughter. He’s expected to get a 10-year sentence for that.

Brown’s case is still pending. He’s charged with aggravated murder, murder and robbery. Pre-trial motions are set for late October in his case.