The Brief Authorities identified the suspect who killed three people and injured seven others at an Idaho In-N-Out Burger before taking his own life as 24-year-old Chad Williams. Williams is a former student at the College of Southern Idaho with no prior criminal records found in court searches in Idaho or Arizona. New details are emerging about the man police say opened fire at an Idaho In-N-Out Burger over the weekend. Records show the accused shooter, 24-year-old Chad Williams, had ties to Arizona, and his family lives in the valley. Police say Williams opened fire at an In-N-Out in Twin Falls, Idaho, killing three people and injuring 7 others before turning the gun on himself.