The State Fire Marshal’s Office says the cause of last week’s fire that killed a father and son in Washington cannot be determined because of the severe damage to the family's home.

However, investigators say there's noting indicating the fire wasn't an accident, the Maine Department of Public Safety said in a Monday news release.

Investigators say the fire started in the basement near the wood stove and quickly spread upstairs.

Steven Rhodes, 53, and his son, Isaac Rhodes, 25, were killed in the Jan. 23 fire on Cattle Pound Road.

The release said Steven Rhodes attempted the put the fire out and then fled the building. Once he realized his son was still in the house, he went back inside to rescue him. Investigators said both men were overcome by the smoke and heat.

Steven's wife, Elizabeth Rhodes, 56, was hospitalized after suffering burns and smoke inhalation in the fire. According to a YouCaring page that was set up to help the family pay for funeral expenses, Elizabeth Rhodes was released from the hospital on Jan. 24.