SHANKSVILLE — A state police fire marshal says he may never be able to determine what caused a fire that destroyed the headquarters buildings at the Flight 93 National Memorial in Pennsylvania.

Trooper Scott Kovach said the fire is still under investigation but says, “I’m not sure how much investigating we’re going to be doing though.”

That’s because the probe might end soon if officials can’t figure out what caused the fire. The investigation has found no signs of arson or foul play in the Oct. 3 fire.

An initial inventory indicated the losses included a flag that flew over the U.S. Capitol on Sept. 11, 2001, the day four planes were hijacked by terrorists.

The memorial and visitor center, under construction about two miles away, weren’t damaged.