The family was from the Benton Harbor, Mich., area, he said.

Investigators believe that the cause of the fire was accidental, the Berrien County sheriff’s office said in a news release on Saturday evening. They found no accelerants or illegal narcotic manufacturing at the scene.

The fire originated in a first-floor room of the motel, where investigators plan to do further forensic testing, according to the news release. The victims were staying in a room on the second floor, and the authorities believe that they died from smoke inhalation.

The sheriff’s office contracted a private security company to test the motel’s fire alarm and smoke detector.

The motel is near a highway in Sodus, about 200 miles west of Detroit. Twenty-seven of the motel’s 60 rooms were occupied at the time of the fire.