PART 1 of 2 PARTS -- see end of part 2 for interesting detail By Nancy Lewis Washington Post Staff Writer In the first juvenile case of the new year, a tall, thin, 17-year-old stood rocking back and forth in D.C. Superior Court yesterday and showed no emotion as a police officer testified about a problem that has become all too typical in the city: young people with guns. The youth, an escapee from the Oak Hill youth detention facility, was charged with numerous weapon violations after he bought tracer bullets for an AK-47 assault rifle from a Maryland arms store and was later found to have an arsenal of loaded assault weapons and ammunition in his Northeast Washington home. Officials said six weapons, including an AK-47, two MAC-11 assault pistols and a .45 caliber semiautomatic pistol, were seized along with more than 100 rounds of ammunition for the weapons, making it one of the largest caches of high-powered weaponry ever recovered from a juvenile in the District. D.C. Superior Court Judge Robert S. Tignor ordered the youth, who was charged as a juvenile, held in maximum security at Oak Hill pending his trial on several weapon charges, including possession of an unregistered firearm, possession of ammunition and possession of a prohibited weapon. Weapon possession charges, which are not legally classified as violent crimes, are not among the offenses for which a youth 16 or older may be charged as an adult. The growth in the number of automatic and semiautomatic weapons during the last five years, many of which have ended up in the hands of teenagers and other young people, has contributed to the city's high homicide rate, according to police. The number of semiautomatic pistols confiscated by D.C. police and other agencies has tripled since 1986, from 485 to more than 1,500 last year. The AK-47, manufactured in the former Soviet Union and its satellite countries, is among 43 types of weapons whose importation into this country was banned in 1989. The MAC-11, which uses a magazine that holds 32 rounds, is not subject to the ban. According to a report by a Department of Human Services official, the youth was sentenced in June to serve a year at Oak Hill on a charge of assault with a dangerous weapon, a stick. He was arrested Dec. 11 after he failed to return from a home visit, and at that time Judge Judith Retchin ordered the youth held in secure detention. On Dec. 20, while in the infirmary for treatment of head injuries he received before he was picked up Dec. 11, the youth allegedly climbed out a window and fled again. Despite the youth's current sentence, Assistant Corporation Counsel Darlene Soltys asked for maximum security detention in the new case to ensure that he will remain locked up. Defense attorney Lauren Kahn argued that detention on the new charge was unnecessary.