KNOXVILLE, Iowa (AP) — Authorities are trying to determine what caused a house fire in central Iowa that caused a 70-year-old woman's death this weekend.

The Knoxville Police and Fire Departments said crews responded to a fire shortly after midnight Sunday, and found a home filled with smoke and two adults sitting on the front porch.

The two victims were placed in a police car to get them out of the weather, and then the woman became unresponsive.

The woman was taken to a nearby hospital where she died. Her name wasn't immediately released.

Authorities are working to determine the cause of the fire.