KNOXVILLE, Iowa (AP) — A Knoxville house fire killed a 77-year-old woman and injured her husband.

Marion County Sheriff Jason Sandholdt says around 11 p.m. Sunday dispatchers received a call about a Knoxville house engulfed in flames with a woman inside.

Sheriff’s deputies attempted to put out the fire but they were unable to enter the home. When Knoxville rural firefighters arrived, they contained the fire and removed the woman from the house.

Emergency responders took Patricia Henning to a nearby hospital, where she later died. Her husband, 79-year-old Ronald Henning, was injured and taken to a burn unit at the University of Iowa Hospitals and Clinics.

The cause of the fire is being investigated.