Police say Edgar Maddison Welch was pulled over Saturday night as a passenger in a traffic stop because he had an outstanding warrant.

Edgar Welch fired an assault rifle inside a Washington, D.C., restaurant in December 2016 while claiming to investigate the "pizzagate" hoax.

He pled guilty to a to a federal charge of interstate transportation of a firearm and ammunition, and a D.C. charge of assault with a dangerous weapon.