EAST ST. LOUIS, Ill. (AP) — A co-defendant in the August 2019 fatal shooting of an Illinois State Police trooper has pleaded guilty to a federal gun charge.

U.S. District Chief Judge Nancy Rosenstengel on Monday ordered 20-year-old Al Stewart Jr. to remain in jail until his sentencing in September.

Stewart was living next door to Christopher Grant in an East St. Louis duplex when Grant allegedly shot to death Trooper Nick Hopkins as a no-knock warrant was being served. In his plea agreement, Stewart said he grabbed a pistol when he heard gunshots, but put it down when he went to a window and spotted Illinois State Police.

Grant has pleaded not guilty to first-degree murder charges in St. Clair County Court.