LEAVENWORTH, Kan. (AP) — A Missouri man who authorities said fired at least 20 rounds at drivers stopped on a bridge between Missouri and Kansas before a driver hit him with his vehicle entered a plea Wednesday to charges in the case.

Jason Westrem, 39, from Houston Lake, Missouri, pleaded no contest to attempted first-degree murder and two counts of aggravated assault using a deadly weapon, Leavenworth County Attorney Todd Thompson said.

Investigators said traffic was slowed by construction on the Centennial Bridge between Leavenworth, Kansas, and Platte County, Missouri, on May 27, 2020, when Westrem opened fire at the vehicles and construction workers, KMBC-TV reported.

Authorities have not released a possible motive for Westrem’s actions.

Master Sgt. David Royer, a soldier at Fort Leavenworth, stopped the shooting by driving into Westrem and pinning the shooter under his vehicle, investigators said.

After the shooting, Leavenworth Police Chief Patrick Kitchens credited Royer with saving “countless lives.”

One person was injured and several rounds struck vehicles, investigators said.

Thompson said the plea agreement was reached with the consent of people involved in the shooting.