His case had become a cause celebre. To his supporters, Stanley "Tookie" Williams, the gang founder who spent his years on death row warning people away from the violent culture he helped to create, was living proof that a condemned killer could be rehabilitated.

But whether he truly had found redemption - and many doubted his sincerity - prosecutors, victims' advocates and death penalty supporters said he still had to pay for the murders of four people in 1979.

The 51-year-old Williams, who acknowledged wrongdoing as a co-founder and leader of the Crips gang in Los Angeles but said he was innocent of the killings for which he was condemned, was executed early this morning at San Quentin State Prison after Gov. Arnold Schwarzenegger declined yesterday to commute his sentence.

"After studying the evidence, searching the history, listening to the arguments and wrestling with the profound consequences, I could find no justification for granting clemency," Schwarzenegger said. "The facts do not justify overturning the jury's verdict or the decisions of the courts in this case."

Williams' case has revived the national debate over what the state should do with death-row convicts who have turned their lives around to become contributing members of society while awaiting execution.

"The fear people have is that if you put a person back on the streets, they're going to do the same kinds of things again," said Bishop H. Gerard Knoche, head of the Delaware-Maryland Synod of the Evangelical Lutheran Church in America. "You could at least commute his sentence so his ministry could continue. Who knows what additionally this man can do, how much further he can develop, even from prison?"

Michael Paranzino, president of Kensington-based Throw Away the Key, said granting clemency based on death-row conversions "gives further incentive for these killers to game the system.

"That's why we have 25 years of frivolous appeals in the Tookie Williams case," Paranzino said. "Once you establish that you can commit any sort of heinous crime you want, as long as you turn yourself around with the inevitable period between conviction and execution, that sends all the wrong signals to would-be killers and to killers, which is: After we catch you, then quickly find God, get a marketing or PR director and start writing books and preaching to kids or whatever the next gimmick is going to be."

Williams was convicted in 1981 of gunning down Albert Owens, 26, a 7-Eleven clerk, during a holdup in Whittier, Calif., and of shooting to death Yen-I Yang, 76, Tsai-Shai Chen Yang, 63, and their daughter Yu-Chin Yang Lin, 43, at their Los Angeles motel a few weeks later.

On death row, Williams repudiated gang violence, wrote anti-gang books and gave anti-gang talks to churches and community groups by telephone.

"If Stanley Williams does not merit clemency," his attorney Peter Fleming Jr. asked, "what meaning does clemency retain in this state?"

Schwarzenegger was not persuaded.

"Is Williams' redemption complete and sincere, or is it just a hollow promise?" he asked. "Without an apology and atonement for these senseless and brutal killings, there can be no redemption."

Schwarzenegger's decision drew immediate criticism from Williams' supporters.

"Too often, I hear the governor and many who are around him talk about his values system," NAACP President Bruce S. Gordon said. "In this particular case, those values seem to be cast aside. There is absolutely no recognition given to redemption."

Williams had reminded some of Karla Faye Tucker, the Texas woman who was convicted of hacking a man to death with a three-foot pickaxe, and then became a born-again Christian while on death row. She became the subject of a clemency campaign supported by leaders as diverse as Pope John Paul II and televangelist Pat Robertson but was executed in 1998 after the Texas Supreme Court rejected her efforts to challenge the state's clemency process. George W. Bush, then governor of Texas, was limited by state law to granting a 30-day stay of execution. He declined to intervene.

Death penalty opponents yesterday criticized a system that they said did not allow for the possibility that people can change.

"I would not be a Christian if I didn't believe in redemption," Knoche said. "Change is real. That's very fundamental to Jesus' teaching."

Knoche joined with other Catholic and mainline Protestant leaders last week in calling on Gov. Robert L. Ehrlich Jr. to commute the death sentence of Wesley Eugene Baker to life in prison without the possibility of parole. Ehrlich declined; Baker was executed.