pat collins talked to the victim and he joins us from metro headquarters in northwest washington with the exclusive story. pat? reporter: dorene, at a metro station, a man sees a beating. he goes to call 911, and he becomes victim number two. for robert joy, it s hard to talk. you see, his two front teeth were knocked out. he had six stitches inside his mouth, two stuch stitches outside. his right eye, black, blue and bloodied. it s a tragedy. that, i mean, for innocent people to get attacked at the subway. reporter: now listen to mr. joy s story. the suitland station, the green line, friday night around 6:30. he s waiting here for his niece to get off the subway. he says he is standing over there, near the station manager s office. he looks over near the gates and he sees some teenagers, about 15 of them, attacking another teen. he says they re all dressed in black, some are wearing masks. that teen is on the ground. he says a woman comes running to him and says, call