Four dead in murder-suicide on South Dakota reservation, police say SEATTLE (Reuters) - A South Dakota man shot and killed three people and critically wounded a fourth person before taking his own life at a residence on a Native American reservation, law enforcement officials said Saturday. Local police cooperating with Sisseton-Wahpeton Sioux Tribal Police had launched an early morning manhunt for the shooting suspect but later said the gunman was among the dead found inside a residence in the city of Sisseton, on the Lake Traverse Indian Reservation. "The Division of Criminal Investigation has located and identified Colter Richard Arbach, 22, Sisseton, as one of the deceased individuals at the scene of the shooting incident," a news release from the state attorney general's office said. Arbach appears to have died from a self-inflicted gunshot wound, the release said. The identities of three other people killed in the incident were not released. A fourth person was sent to hospital with critical wounds, law enforcement said. The motive behind the killings was not yet clear. Reporting by Victoria Cavaliere; Editing by Raissa Kasolowsky