Valley Regional Fire Authority investigators have determined that the cause of the fatal house fire at 5034 Elliot Court SE in Auburn on Sunday afternoon was arson.

And according to the King County Medical Examiner, the woman whose body was found in the burning home set the fire herself.

“The Medical Examiner classified her death as a suicide,” said Auburn Police Commander Mike Hirman. “We are conducting our own investigation just to make sure no one else was involved. But at this point, all indications are suicide.”

According to investigators, the fire began in the second-floor master bedroom of the home, where firefighters found the woman’s body. As of Wednesday afternoon, the King County Medical Examiner had not yet confirmed her identity.

Multiple neighbors called 911 at 3:46 p.m. after hearing an explosion and breaking glass and seeing heavy smoke and flames boiling out of the upper floor windows. Three fire engines, one ladder truck and one medical aid unit from the VRFA responded to the fire and applied water to the second-floor before entering the building. The woman was quickly found and determined to be dead. Firefighters then focused their efforts on containing the fire to the second floor and keeping it from spreading to nearby homes.

The fire destroyed the home’s second floor. The first floor and basement suffered heavy water damage. Damage to the structure and contents is estimated at $170,000.

Auburn Police detectives are investigating the incident with the King County Medical Examiner to determine the cause of death.