Authorities on Saturday night found two parents and their three children dead of unknown causes inside their Utah home, officials said.
Officers arrived at the Springville home and discovered the bodies of the mother and father, both in their thirties, along with their three children aged between 11 and 14 years old, Springville Police Department Lieutenant Dave Caron said.
There were no signs of trauma on any of the bodies, prompting officials to believe that the family may have succumb to carbon monoxide poisoning, Caron said. But tests of the air inside the house, which had aired out before police arrived, did not show unsafe levels, Caron said.
"There is no obvious cause of death. The only way we are going to determine this is through an autopsy," Caron said.
There was no indication that there was any threat to the community, Caron said.
The family lived in a duplex, and the residents living in the other home were unharmed and did not report hearing anything unusual throughout the day, Caron said.
Springville is a city of roughly 30,000 roughly 50 miles (80 km) south of Salt Lake City.
(Reporting by Curtis Skinner in San Francisco, editing by William Hardy)