MADISON, Wis. -- Fire investigators still haven't nailed down the cause of a fire at the Sigma Phi Epsilon fraternity house in Madison.

City officials have given the fraternity permission to demolish the 8,000-square-foot house, which will happen after an insurance settlement is complete.

Fire investigators said they have all the scientific evidence that they're going to get but were hoping to get more information from people who witnessed the fire.

Madison Fire Department Captain Bradley Olson said it's been difficult to find people to interview.

The fire happened May 13, and Olson said many possible witnesses left town for the summer soon after the fire.

Olson said it isn't even clear if someone intentionally set the fire or if it was accidental.

Officials estimated the damage to the building and its contents at $750,000.