MINEOLA, N.Y. (AP) _ Nine youths who descended on their victims ''in a frenzy, like sharks'' were charged in a series of robberies and attacks during a rap concert Sept. 10 that left one person dead and 12 injured, police said.

Police arrested the suspects, ages 16 to 22, at their homes in Brooklyn's Bedford-Stuyvesant section late Friday and early Saturday, the police said.

Police were led to the suspects after they bragged about the attacks, which took place at the Nassau Coliseum on Long Island, said Detective Sgt. John Nolan, head of the Nassau County homicide division.

In Philadelphia, two youths were shot and hundreds of others involved in fights Friday night at two theaters premiering the rap movie ''Tougher Than Leather.'' Neither shooting victim was seriously injured.

At the Long Island concert, the youths walked in clusters, making squealing noises to distract their victims, and snatched their jewelry, Nolan said.

If the victim resisted, Nolan said, the youths would ''surround him, envelop him, beat, stab and slash him with razor blades before he knew what had happened.''

''They were in a frenzy, like sharks feeding,'' Nolan said.

Julio Fuentes, 19, was stabbed to death after chasing youths who ripped a gold chain and a four-inch gold M from his girlfriend's neck, police said.

Five other concert-goers were stabbed, three were slashed with razors, and four were punched, kicked or clubbed, police said.

Four of those arrested were charged with murder and jailed without bail. Other charges included larceny, riot and conspiracy.