BOSTON (AP) _ A teen-ager testified he pretended to rape the victim in a Halloween 1990 gang rape and murder because he feared other members of the mob would attack him.

''I felt I had to do something or they would turn on me,'' Michael Williams said Wednesday.

Williams, 17, is the first of eight defendants to go on trial for the assault on Kimberly Rae Harbour, 26, who died after being raped repeatedly and stabbed 132 times in Franklin Park in Boston's Dorchester section.

Harbour, who had a 7-year-old daughter, pleaded for her life, but was ignored, Williams said.

Defense lawyer William J. Doyle has argued Williams, charged with juvenile delinquency, was forced to participate in the attack by members of the gang called the Pistons.

Daniel C. Mullane, assistant district attorney for Suffolk County, has said the defendant shares equal guilt, even if he didn't rape or stab Harbour.

Williams said he was with the gang when they cornered Harbour and carried her to the park. He said he stayed with them because he was afraid of running away.

''They would have caught me,'' he said. ''They would have cut me up.''

He said he kicked her twice.

Williams and friends who testified Tuesday said members of the Pistons had beaten him up other times because he hadn't joined the gang.

In the attack, Williams said he was so scared of being hurt that he unzipped his pants and got on top of Harbour when one gang member, Ezekial Hogan, told him, '''Go ahead Michael, it's your turn.''' He denied raping the victim.

Williams is being tried as a juvenile after a judge ruled prosecutors failed to show he could not be rehabilitated and he agreed to testify against the others.

Williams, who admitted he never tried to stop the assault, quoted Hogan as saying, '''Look at the way her skin cuts.'''

Russell Harbour, the victim's father, left the courtroom during testimony and was heard sobbing in the corridor.

Cases involving four juveniles - Dave Sampson, 17, and Anthony Ayala, Terrance Wade and Hogan, all 16 - were transferred to adult court. They and three adults - William Corey James, Che Barnes and Carlos Garcia - face charges of first-degree murder, aggravated rape and robbery.

If convicted, Williams would be held in state custody until age 18. He could be held another three years if the jury determines he cannot be rehabilitated.

The other defendants would face mandatory life prison terms without parole.