"On December 29, 1953, in New Orleans Charity Hospital, I entered the world kicking and screaming in a caesarean ritual of blood and scalpels. Because this was 1950s, pre-Civil-Rights Louisiana, my 17-year-old mother, a 'colored woman,' was deprived of anesthetics as her torso was slit from sternum to pubic bone. Over and over again, she sang the Christmas carol Silent Night to distract her from the pain."

So began the turbulent life of Stanley Tookie Williams III, according to his memoir, Blue Rage, Black Redemption, which tells the story of the murderer, gangster and Nobel Prize nominee whose execution this morning was the most-debated death penalty case in America for decades.

Williams was a paradox for the justice system and for Arnold Schwarzenegger, the Governor of California who denied his last appeal: could he be redeemed for a crime he would not admit?

On the one hand, he seemed a model of rehabilitation. The co-founder of the Crips, a street gang that has claimed thousands of lives in America's inner cities, Williams freely confessed his violent past. He had dedicated the last ten years of his imprisonment to writing against gangs, and setting up a "peace protocol" for gangs to sign truces and disband.

But on the other, he would never admit to any part in the murder of four people 25 years ago of which he was convicted. Ballistic evidence, eyewitness accounts and former cellmates all pointed to the guilt of Williams, then a musclebound 25 year old, who was duly convicted of raiding a 7-Eleven convenience store and a Los Angeles motel within two weeks of each other in the spring of 1979.

In the store, he shot Albert Owens, a cashier, and in the motel, he killed Yen-I Yang, his partner, Tsai-Shai Lin and their daughter, Yee-Chen Li. All four victims were shot at close range with Williams's shotgun.

Hours after he killed Owens, Williams was said to have boasted: "You should have heard the way he sounded when I shot him." He referred to the Yen family slightingly as "Buddha-heads".

Looking back on his trial, Williams said that when he was arrested, he was a gang member through and through. "Cripping was all I knew. I lived it. I breathed it. I walked it and I talked it." Although he pleaded his innocence he plotted to blow up a prison bus and kill his guards.

When he came to face the jury: "I was darned near twice this size. I had an indelibly entrenched grimace on my face. I had total disdain for the law enforcement system and it showed. And I was shackled," he told The New York Times.

But Williams's anger appeared to fade and in the mid-1990s, on death row at San Quentin, California's oldest jail, he said "redemption infused itself into my life". In 1996, Tookie Speaks Out Against Gang Violence, a series of children's books was published. In Gangs and Self Esteem and Gangs and the Abuse of Power, Williams seemed to preach against the life that he had exemplified.

In 1998, his Life in Prison was published, followed by his memoir. In 2004, Williams's life was dramatised in a television film Redemption, starring Jamie Foxx, and a New Jersey branch of the Crips signed a truce with their longheld rivals, the Bloods, citing inspiration from their former leader.

But as his death sentence slowly neared, and as he was nominated for the Nobel prizes for peace and literature, Williams would not confess.

His transformation was scrutinised. In denying a stay of execution, Mr Schwarzenegger quoted from the foreword of Life in Prison, which dedicated the book to the brutal murderer George Jackson, as proof that his rehabilitation was uncertain. The Governor also criticised Williams for his limited remorse for the actions of the Crips, which he called "a tragedy of our modern culture".

Just two weeks ago, Williams gave a final interview to The New York Times, and still he argued his narrow case: that he was both innocent and reformed.

"To threaten me with death does not accomplish the means of the criminal justice system or satiate those who think my death or my demise will be a closure for them," he said.

"Their loved ones will not rise up from the grave and love them. I wish they could. I sympathise or empathize with everyone who has lost a loved one. But I didn’t do it. My death would not mollify them."

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