The Missouri State Highway Patrol said seven people have been killed in overnight shootings in south-eastern Missouri and that the gunman is also dead.
Sergeant Jeff Kinder said the 36-year-old suspect was found dead early on Friday from an apparent self-inflicted gunshot wound.
Investigators said the attacks took place in multiple locations in and around the town of Tyrone, about 65 kilometres north of the Arkansas border.
Authorities have not named the victims or the gunman. The victims were found at four different homes.
One injured person was taken to a hospital.