A 21-year-old man being held in the D.C. jail as a fugitive from a Virginia state mental hospital was found dead in his cell early yesterday, the fifth inmate to hang himself in two months, police officials said.

D.C. Corrections Department spokesman Leroy Anderson identified the latest apparent suicide victim as Glenn Snow of Arlington. Anderson said Snow had attempted suicide by hanging once before on May 18, two days after he was arrested by city police.

Snow was found hanging yesterday by a makeshift bedsheet rope attached to an air vent in his cell. His body was discovered at 2:30 a.m. by correctional officers who had last made a "bed check" at 2 a.m., an official said.

Arlington police officials said Snow had been sent in May to Southwestern State Hospital In Marion, Va., for observation. Police said shortly before Snow was to return to Arlington, he escaped and drove a stolen car to Washington where he was involved in an accident on the 14th Street Bridge on May 16.

Snow's mother, Isabel Snow, also of Arlington, said her son had been "acting strangely" at the Arlington jail and had sent her a letter saying he was the Boston Strangler and wanted to "take a nice, long rest."

Mrs. Snow and Arlington police officials said Snow, nicknamed Bucky, had a long record of auto theft charges dating back to when he was 14 years old.

Anderson said Snow was interviewed four times by psychiatrists following the May 18th incident in which he had tried to hang himself while confined to the jail infirmary.

Snow's mother said yesterday she did not understand why her son was confined in the jail instead of being kept in a hospital. "I want to find out what happened," she said.

Anderson declined to discuss Snow's record at the jail, citing a current court case before Chief Judge William B. Bryant of the U.S. District Court.

That case, Campbell vs. Magruder, alleges in part that the jail is unable to properly care for inmates with emotional problems.

Anderson said the other four hangings included one that occurred on May 5 at the jail's detention unit at D.C. General Hospital. Other hangings occurred at the jail on May 14, June 15 and June 23, Anderson said.

A source within the jail said Snow was considered "suicidal" and that his jail cell had a tag on it indicating that Snow might harm himself. "We can't watch them every minute. I think the officers did well checking on him just 30 minutes after a formal check," the source said.

"That's the whole question of the suit," the source said. "Is a jail a place for an emotionally disturbed person to be?"