FORT WORTH, Texas — A prosecutor says a Fort Worth police officer failed to follow his training when he shot a man who was walking in his neighborhood while holding a barbecue fork.

Tarrant County prosecutor Tamla Ray during opening statements Tuesday in the trial of officer Courtney Johnson challenged Johnson’s assertion that his shotgun accidentally discharged in the 2015 shooting.

The 35-year-old officer is charged with aggravated assault by a public servant in the shooting of Craigory Adams.

Police have said Johnson was responding to a homeowner’s call about a knife-wielding man.

Authorities have denied race was a factor. Johnson is white and Adams black.

Adams, who has a mental impairment, had dropped the fork and gone down on his knee when he was shot. He suffered an arm wound.