Allen was already serving a life sentence for one murder when he was convicted of organizing the killing of three more people from prison, including a witness who had testified against him.

They argued that his execution would constitute cruel and unusual punishment and requested that he be granted clemency by California Governor Arnold Schwarzenegger, which was refused.

Allen then arranged a date between Schletewitz and Mary Sue Kitts (his son Roger's 17-year-old girlfriend) for the evening, during which time the burglary took place.

Allen conspired with fellow inmate Billy Ray Hamilton while in Folsom Prison to murder the various witnesses who had testified against him, including Bryon Schletewitz.

On September 5, 1980, Hamilton and his girlfriend, Connie Barbo, went to Fran's Market while Bryon Schletewitz, who testified against Allen, was working.

There, Hamilton murdered Schletewitz and fellow employees Josephine Rocha, 17, and Douglas White, 18, with a sawed-off shotgun and wounded two other people, Joe Rios and Jack Abbott.

The jury returned a unanimous verdict of death, and the Contra Costa County Superior Court sentenced Hamilton on March 2, 1981.

Allen was convicted of three counts of first-degree murder with special circumstances and was received onto California's death row at San Quentin State Prison on December 2, 1982.

Associate Justice Joseph Grodin's opinion referred to Allen's crimes as "sordid events" with an "extraordinarily massive amount" of aggravating evidence.

In her opinion for the panel, Judge Kim McLane Wardlaw concluded: Deputy California Attorney General Ward Campbell stated in an interview: On January 13, 2006, California Governor Arnold Schwarzenegger refused to grant Allen clemency, stating that "his conduct did not result from youth or inexperience, but instead resulted from the hardened and calculating decisions of a mature man."

Judge Kim Wardlaw writing for the panel of judges Susan Graber, Richard Clifton, and herself: The United States Supreme Court declined to hear the case, albeit over the dissent of Justice Stephen Breyer, who stated: "I believe that in the circumstances he raises a significant question as to whether his execution would constitute 'cruel and unusual punishment.'"

Correctional officers familiar with Allen later stated that while he was on death row, he often walked without assistance and alleged that he was not blind, as he was able to read his mail.

[9] Allen was executed by lethal injection on January 17, 2006, the day after his 76th birthday, at California's San Quentin State Prison.

He remains the most recently executed inmate in California as of March 2019 when the imposition of the death penalty was suspended in the state by Governor Gavin Newsom.

[10] Allen was assisted in the death chamber by four correctional officers, though a media observer stated that he was clearly moving under his own power.

Allen wrote in his final statement, which Warden Steven Ornoski read immediately following the execution, "My last words will be 'Hoka Hey, it's a good day to die.'