Three people were killed and another seven were injured when a gunman opened fire outside an In-N-Out Burger restaurant in Twin Falls, Idaho, on Saturday, authorities told ABC News on Sunday.

The suspected shooter, whom officials identified as 24-year-old Chad Williams, died from an apparent self-inflicted gunshot wound after being confronted by an armed off-duty Idaho state trooper and a private citizen, the Twin Falls Police chief said at a news conference on Sunday.

Five of the seven injured victims remained hospitalized on Sunday afternoon, including two in critical condition, the chief said.