COUNCIL BLUFFS, Iowa (AP) — The man who was killed in Monday night’s crash near Oakland was a volunteer with Democratic presidential candidate Elizabeth Warren’s campaign.

The Pottawattamie County Sheriff’s Office says 22-year-old Zachary Crombie Presberg was killed Monday night when the car he was driving on U.S. Highway 6 collided with two trucks as he tried to pass one of them.

A statement from Warren’s campaign says Presberg joined the campaign this summer after graduating from Lawrence University in Appleton, Wisconsin, to organize voter meetings and build relationships in Cass County. He continued his service to Warren’s campaign as a volunteer after his fellowship ended.

He was a native of Piedmont, California.

Warren said in the statement that she and her husband “are heartbroken over Zac’s passing” and added that “Zac represented the very best of us.”