A federal judge yesterday ordered that a former aspiring firefighter charged with burning houses at a subdivision under construction in Charles County be returned to jail for violating the terms of his pre-trial release.

Prosecutors had requested that Roy T. McCann be taken into custody, arguing in court papers that they suspect he was involved in setting fire to an automobile seat and other debris in the La Plata area.

Judge Charles B. Day's ruling was based not on that fire but on McCann's admitted violation of an order requiring him to be accompanied by his mother while outside her home one day last month, said McCann's attorney, Joshua Treem.

McCann, 23, of Waldorf, is one of five men charged in fires Dec. 6 that damaged or destroyed two dozen unoccupied houses at Hunters Brooke, an upscale development in Indian Head, about 30 miles south of Washington. He is charged with conspiracy to commit arson and numerous counts of arson.

Shortly after his arrest in December, McCann was released on conditions that included limited travel outside his mother's house. A judge recently granted him permission to leave the residence Sept. 10, on the condition that he be accompanied by his mother.

Secretly under surveillance, McCann was observed traveling in a pickup in the company of two men and, at another point, alone in his car, Assistant U.S. Attorney Donna C. Sanger wrote in the court papers. He and the other men arrived at the Charles landfill late that morning but left immediately, turning onto a gravel road near Piney Church Road.

Five days later, a trash heap was found on private property nearby, Sanger wrote. In the debris were papers identifying McCann and his family members, including canceled checks from McCann's mother, Barbara Harrison, Sanger wrote. Several of the items, including the automobile seat, had been burned, she wrote.

McCann is one of two suspects still awaiting trial in the Hunters Brooke fires. Two others have pleaded guilty, and the alleged ringleader, Patrick Walsh, 21, was found guilty this month on 35 counts of arson and one count of conspiracy.