A prosecutor said Monday that human blood was found on the clothes of a youth who he says "admitted he stabbed" a Utah tennis buff when he tried to defend his parents during a mugging on a subway platform.

The alleged ringleader of a gang, Yull Gary Morales, 19, made written and videotaped confessions about the violence in Midtown Manhattan substation Sept. 2, said Assistant District Attorney Thomas Shiels."He admitted he stabbed Brian Watkins himself," Shiels said.

Some of his seven co-defendants also said Morales wielded the knife that killed Watkins, 22, who traveled to New York City with his family from Provo, Utah, to watch the U.S. Open Tennis Tournament.

The co-defendants also said Morales had the knife out before the robbery and had the weapon in his pants' pocket when he was arrested the following day, Shiels said at the arraignment in state Supreme Court in Manhattan.

Co-defendants also pegged Morales as the organizer of the mugging.

All eight youths pleaded not guilty to second-degree murder, robbery and assault. All were ordered held without bail. They were to return to court on Oct. 3 for a hearing before Justice Edwin Torres.

Outside court, Morales' lawyer, Joel Lutwin, said his client has "already been convicted in the media" and will have a tough time getting a fair trial.

If convicted, the suspects would face 25 years to life behind bars.

The death of Watkins highlighted the plight New Yorkers face with increasing violence, both random and intentional and drew cries from city officials, including Mayor David Dinkins, who asked New Yorkers to reach out and help those being victimized by helping police to track down criminals.

City officials called the attack an exception among visitors, pointing to some 20 million tourists who visit the Big Apple each year.

The subway system is used by about 3.5 million riders a day. Watkins was the 18th person killed in the subway this year.