DELAWARE, Ohio (AP) — Authorities say carbon monoxide may have caused the deaths of four family members at a home in central Ohio.

Officials in Genoa Township say first responders went to a home shortly before 1:30 p.m. Thursday after receiving a call from a concerned relative and found elevated levels of carbon dioxide inside the residence.

The family members haven’t been identified and a cause for their deaths hasn’t been officially determined.

Genoa Township is about 20 miles north of downtown Columbus in Delaware County.