A young white man has been arrested and is believed to be the sole shooter. He has been identified by US media as 21-year-old Patrick Crusius, a resident of the Dallas area.

CCTV images said to be of the gunman and circulated on US media show a man in a dark T-shirt wearing ear protectors and brandishing an assault-style rifle. Police said the Walmart was “at capacity” with shoppers buying back-to-school supplies at the time of the attack.