Attorney Elliot Weinstein also said Ismael Vasquez's accusers were "a cast of society's misfits" and that prosecutors' key witnesses told lies in order to avoid long jail terms.

Vasquez, 27, his 22-year-old brother Luis, Harold Parker, 31, and Scott Davenport, 31, are all charged with kidnapping and murdering Io Nachtwey, who moved to Massachusetts from Hawai'i just months before she was killed. Prosecutors say they killed her to send a message to other recruits in their fledgling gang.

Luis Vasquez is also charged with raping Nachtwey before she was struck with a martial arts weapon and stabbed a dozen times on Nov. 3, 2001. Her body was thrown from a railroad bridge into the Charles River, where joggers found it the next day.

In his closing argument in Suffolk Superior Court, Weinstein attacked the credibility of Ana White and Lauren Alleyne, who each pleaded guilty to helping kill Nachtwey and testified for the state.

Under the deal they struck with prosecutors, the two women could be out of prison in about five years, he said. The Vasquez brothers, Parker and Davenport face up to life in prison if convicted.

"These young women have a powerful reason to blame others," Weinstein said. "Would each lie to regain their freedom? Would each lie to avoid spending the rest of their lives in state prison? Of course they would, and they did."

He also said Ismael Vasquez had never been to the bridge where Nachtwey was killed.

"He was far away, on the Cambridge side of the river, when (Nachtwey) was killed," Weinstein said.

Luis Vasquez's lawyer, Michael Doolin, gave his closing argument after Weinstein.

Nachtwey frequently panhandled in the Pit, a brick plaza near the entrance to the Harvard Square subway station. It was here that she became friends with White and Alleyne. It was also in Harvard Square, prosecutors say, that the Vasquez brothers and Parker recruited the three young women to join their gang.

On Halloween night 2001, the recruits were ordered to steal valuables as a gang initiation. But when Nachtwey's friends failed to bring back any goods, Nachtwey was killed to send a message that disobedience would not be tolerated, prosecutors said.

White, 21, recalled on the witness stand that Nachtwey screamed and begged for her life as she was being stabbed over and over.

"She was just screaming," White said. "Just horrible screaming."

White put her hand over Nachtwey's mouth while Alleyne held her down as Davenport stabbed her. But it wasn't until one of the men cracked a pair of nunchucks against Nachtwey's skull that the screaming stopped, White said.

Davenport, who was recruited because he had a car, initially refused to participate in the killing, but he later agreed to stab Nachtwey after Ismael Vasquez told him, "If you don't, you won't walk out of here," White said.

After Nachtwey was killed, Davenport, still carrying the knife, said, "What a rush," according to White.

Weinstein called White "a little manipulator" whose parents, both doctors, refused to bail her out of jail.

"This manipulative deceiving sociopath did everything in her power to try to get out of jail," including, he said, trying to recruit friends to sell drugs and prostitute themselves to earn her bail money.