LOGANSPORT, Ind. (AP) — Police say there were no working smoke detectors in a rural northern Indiana home where six members of an extended family died in a fire.

Indiana State Police Sgt. Tony Slocum also said Thursday there’s no evidence the fire outside Logansport was intentionally set.

Slocum says investigators have completed an inspection of the entire burned-out home and debris. He says major appliances such as the stove and water heater have been ruled out as sources of the fire early Wednesday. Slocum says there’s “some evidence indicating the fire could have been caused by an electrical issue, but due to the destruction,” the cause remains undetermined.

State Fire Marshal Jim Greeson said Wednesday that the investigation into the cause could take weeks because of the destruction.