A former aspiring volunteer firefighter awaiting trial on charges of burning houses last year at a subdivision under construction in Charles County violated the terms of his release and may have set another fire, federal prosecutors said.

In court papers filed last week, prosecutors asked a judge to order that Roy T. McCann, 23, of Marbury be taken into custody. They said they suspect he was involved in setting fire to an automobile seat and other debris in the La Plata area.

"It is difficult to imagine anything that could be a more flagrant violation of the court's conditions of release than for the defendant to trespass and set another fire on private property," Assistant U.S. Attorney Donna C. Sanger wrote Sept. 16.

McCann 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 electronic monitoring and limited travel outside his mother's house. A judge recently granted him permission to leave his mother's residence from 9 a.m. until 1 p.m. on Sept. 10, on the condition that he be accompanied by his mother.

Secretly under surveillance, McCann was observed traveling in a pickup truck in the company of two other men and, at another point, was alone in his own car, Sanger wrote. He was not accompanied by his mother, she wrote.

He and the other men arrived at the Charles County 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. Among 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 set on fire and destroyed, she wrote.

Joshua Treem, a lawyer for McCann, declined yesterday to comment on the allegations.

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

In part because the suspects are white and most of the homeowners at Hunters Brooke are black, the fires fueled a perception that racism persists in Charles County.