The man who shot dead three people and injured more than half a dozen others in the US state of Idaho, died from a self-inflicted gunshot wound. Three people died and seven others were injured at the recently opened restaurant in the southern Idaho city of about 56,000 people. Hicks said an off-duty state trooper and an armed citizen - whose identities weren’t immediately disclosed - both fired back and diverted the gunman away from the restaurant. Hicks said detectives are working to determine Williams’ motivations, and said the suspect’s family was co-operating fully with law enforcement. The In-N-Out had opened just about a week earlier, on July 24, as part of the California-based company’s recent expansion to Idaho.