Fire investigators cannot determine what caused two mobile homes to burn down late last month.

On Aug. 25, the two residences in the trailer court at 1720 PG Pulpmill Road were destroyed by an afternoon blaze. It was stated at the time of the incident that the point of origin seemed to be in the rear of Unit No. 18, an unoccupied unit containing gunpowder and other firearms paraphernalia -- all apparently possessed and stored lawfully -- which exploded during the fire. The flames spread to Unit No. 17, occupied by a teenaged boy and his friend when the fire started. Both escaped uninjured.

"It is believed that the fire began outside the homes. Due to the extent of fire damage in this area, a point of origin could not be determined."" said Prince George's chief fire prevention officer Dennis Perrault on Wednesday.

The two residences were engulfed in flames when fire crews arrived. Neither could be saved, but firefighters were able to keep the fire from spreading to other nearby mobile homes.