Madison Fire Department officials are still investigating a fire that occurred last Friday morning at the Sigma Phi fraternity house. The fire caused approximately $15,000 in damage.

Initially, crews were unable to locate the source of the smoke when they responded at approximately 6 a.m. Friday morning, so a water stream was directed down a vent.

After extensive searching and interviews with residents, crews discovered a secret room in the basement area, unknown to fire crews, but used by residents. The door to the stairwell that led to the room was made to appear as though it was part of the basement wall.

After gaining access to the room, crews were able to quickly extinguish a chair still smoldering after the water was directed down the vent from outside.

According to the fire department, residents described the hidden room as their Chapter room. The room itself is located underground, a level below the primary basement area, and has no direct access to the outside. The room contained various candles and a podium-like structure, surrounded by church style pews for seating.

By the time fire crews arrived, residents had already evacuated the building, located at 106 N. Prospect Ave. in the University Heights Neighborhood. No one was injured.

Known as the Bradley House, the building was designed by architect Louis Sullivan and was sold to the fraternity by the Bradley family. After a disastrous fire in 1972, the house was rebuilt in 1976 and named a National Historic Landmark.