Former gang leader and convicted murderer Stanley "Tookie" Williams has been executed at San Quentin prison in California.
Prison officials Williams was put to death by lethal injection shortly after midnight, local time (and was formally pronounced dead at about 0835 UTC). The execution was carried out hours after the U.S. Supreme Court rejected a final appeal for a delay.
Williams was convicted in 1981 of murdering four people during two separate robberies (two years earlier). He had always denied having any role in the killings.
A co-founder of a notorious street gang known as the Crips, Williams later wrote a series of books warning children and teenagers about the dangers of gang life. Death-penalty opponents and Hollywood celebrities argued that his life should be spared because of his activism.
California Governor Arnold Schwarzenegger said he rejected a request for clemency on Monday because Williams never apologized for the murders.
