BOZEMAN, Mont. — Republican multimillionaire Greg Gianforte won Montana’s only U.S. House seat on Thursday despite being charged a day earlier with assault after witnesses said he grabbed a reporter by the neck and threw him to the ground.

Gianforte, a technology entrepreneur, defeated Democrat Rob Quist to continue the GOP’s two-decade stronghold on the congressional seat.

Gianforte was a strong favorite throughout the campaign and that continued even after authorities charged him with misdemeanor assault. Witnesses said he grabbed a newspaper reporter and slammed him to the ground after being asked about the Republican health care bill.

Gianforte dropped out of sight after he was cited by police and ignored calls on Thursday by national Republicans to apologize.

He emerged at his victory celebration where he said he accepted responsibility for the incident. “Last night I made a mistake and I took an action I can’t take back and I am not proud of what happened,” Gianforte said.