Idaho In-N-Out Burger shooting motive still a mystery as armed citizen speaks out

Police are still working to determine why a 24-year-old gunman opened fire at a crowded In-N-Out Burger in Twin Falls, Idaho , killing three people and wounding seven others before taking his own life after taking fire from a bystander and an off-duty Idaho state trooper. Twin Falls Police Chief Matthew Hicks said Sunday that investigators were confident Chad Williams acted alone in Saturday's attack, but detectives had not yet established a motive or fully traced his movements before the shooti