OSHKOSH, WI (WTAQ) - An early morning fire at an Oshkosh duplex leaves one person and a dog dead.

Fire officials haven’t determined the source yet – or, whether it was accidental.

Police report they got a call about a fire in the upper portion of a duplex at about 4:20 a.m. Saturday. Both the person and the dog were dead when officers arrived.

Crews were reportedly on the scene for about six hours.

The identity of the dead person hasn’t been released. An autopsy is being conducted by the Winnebago County Coroner’s Office.