A 15-year-old boy shot and killed three siblings before turning the gun on himself in Alaska, authorities have announced.
The teenager was found dead with an apparent self-inflicted gunshot wound at a home near the city of Fairbanks after a neighbour reported shots had been fired, a spokesperson for the Alaska State Troopers said.
Officers responding to the call discovered four children, aged five, eight, 17, and 15, dead inside the property.
They said the children's parents were not home at the time of the incident and three other children, all under the age of seven, were found unharmed.
Authorities are still investigating any potential motive behind the deadly incident, according to the Associated Press.
Troopers added the weapon used was a "family gun" but it is "all still part of the ongoing investigation".
It has also not been made clear if the 15-year-old had previously been in trouble with law enforcement and enquiries surrounding that are still taking place.
The bodies of the children have been taken to the state medical examiner's office for further investigation and children's services have been informed.