An Army veteran pleaded not guilty Wednesday to assaulting a 13-year-old boy who the suspect said refused to remove his hat during the national anthem at a rodeo in Montana.

Attorney Lance Jasper has told the Missoulian that defendant Curt Brockway, who suffered a traumatic brain injury from an automobile crash while he was stationed at Fort Lewis, Washington, believed he was doing what President Donald Trump wanted him to do.

�His commander in chief is telling people that if they kneel, they should be fired, or if they burn a flag, they should be punished,� Jasper told the newspaper. �He certainly didn�t understand it was a crime.�

Jasper is seeking a mental health evaluation for Brockway, 39, of Superior, Montana.

Brockway told investigators the boy cursed at him when he asked him to remove his hat at the Aug. 3 rodeo.

Witnesses have said Brockway picked the boy up by his neck and slammed him to the ground. The boy suffered a skull fracture, court records said.

The interaction drew national attention and Jasper said he received death threats along with Brockway and his family. Security was tight for Wednesday�s hearing before District Judge John Larson, with 16 law enforcement officers present.

Brockway remains free without bond. His next hearing is Oct. 23.

Larson reinstated Brockway�s probation from a conviction for assault with a weapon in 2010.

Jasper did not immediately return a phone call Wednesday from The Associated Press seeking further comment.

(AP)