A teen-ager made his mark in Arlington police history early yesterday morning when he slipped off a handcuff and became the first suspect to escape from the county's four-year-old detention center.

Police said the 17-year-old youth, who was arrested with a companion for allegedly breaking into Evans Distributors, a jewelry outlet store at 3800 Arlington Blvd., escaped about 4:55 a.m. from a basement room used by police for questioning juveniles.

According to police, the youth was handcuffed by one wrist to a desk while Office Joseph Peralta went across the hall to get some forms. When Peralta returned less than a minute later, the youth had vanished.

"He could have had a handcuff key or picked the lock," said police spokesman Tom Bell. "But I don't know about picking the handcuff lock -- that's almost impossible." Bell also suggested that the handcuff may not have been securely fastened, allowing the youth to simply slip away.

Police have charged the man arrested with the youth, Daryl E. Thomas, of 3812 8th St. NW in the District, with breaking and entering. Thomas remains in custody under $5,000 bond, and the unidentified teen-ager remains at large.