A family of five, including three children aged between four and 12, were found shot to death inside a US apartment.
Investigators said a gun was found near one of the bodies, and it appeared no one outside the family was responsible for the shootings.
Maine state police Sgt Chris Harriman said murder-suicide is one of the scenarios being investigated, but that determination will be made by the state medical examiner's office.
Investigators said a family friend had contacted a worker at the apartment complex in Saco worried about the well-being of the family.
The worker entered the apartment and discovered one body, then immediately called police.
Police found the bodies in three different rooms. Police described the firearm found in the apartment as a long gun. Shell casings were also recovered.
Officials said post-mortem examinations were scheduled for today.