San Francisco ? The California Supreme Court refused Wednesday to halt the scheduled execution of convicted killer Stanley Tookie Williams, the Crips gang founder who became an anti-gang activist while in prison and whose supporters claim has redeemed himself.

In a last-ditch legal move, defense attorneys petitioned the high court earlier this month, alleging shoddy forensic testing and other errors may have wrongly sent Williams to San Quentin State Prison, where he is scheduled to die by injection Dec. 13.

Attorneys for Williams, author of a series of anti-gang books for children, wanted to re-examine ballistics evidence that showed his shotgun was used to kill three people during a 1979 motel robbery in 1979.

The defense claimed the forensic evidence was “junk science,” but prosecutors said that allegation was “based upon innuendo, supposition and the patent bias of (Williams’) purported expert.”

“The extraordinary relief Williams sought is reserved for those cases which have legal merit,” said Nathan Barankin, spokesman for Atty. Gen. Bill Lockyer.

The high court voted 4-2 without comment to deny the inmate’s petition, with Chief Justice Ronald George voting to reopen the case.

Barbara Becnel, executive director of Neighborhood House of North Richmond, and actor Jamie Foxx, holding a cell phone, listen to a jail call Wednesday from Stanley Tookie Williams, as part of a rally to demonstrate against the pending execution of Williams in Los Angeles. The co-founder of the Crips gang is scheduled to be executed Dec. 13.

“We think the chief justice’s dissent highlights the seriousness of the issues raised,” defense attorney Jonathan Harris said. He was unsure whether he would ask the federal courts to intervene again.

Gov. Arnold Schwarzenegger could also still intervene. He has agreed to hear Williams’ clemency petition, and if clemency is granted it would commute the inmate’s sentence to life without parole.

“What I want to do is make sure we make the right decisions, because we’re dealing here with a person’s life,” Schwarzenegger said Wednesday.

The high court’s ruling came as death penalty opponents rallied around the state urging the governor to spare Williams’ life because of his turnabout on death row.

His supporters include celebrities Snoop Dogg, Jamie Foxx, Elliott Gould, Danny Glover, Laurence Fishburne, Ted Danson, Mike Farrell, Russell Crowe, Richard Dreyfuss, Gabriel Byrne and Bianca Jagger.

Williams, condemned in 1981, has maintained his innocence. Among his claims is that fabricated testimony sent him to death row. He also says prosecutors violated his rights when they dismissed all potential black jurors from his case.

While in prison, Williams has campaigned for an end to youth gang violence while co-authoring anti-gang books for youngsters.