LOS ANGELES (AP) -- Gregory Powell, who was convicted of killing a Los Angeles police officer during an infamous kidnapping that inspired the true crime book and movie "The Onion Field," has died in prison at age 79, authorities said Monday.
Powell died late Sunday in a hospice at the California Medical Facility, a men's prison in the Northern California city of Vacaville, according to the California Department of Corrections and Rehabilitation.
Powell spent nearly 50 years behind bars and was denied release several times, including last year when he told a parole board he was dying and wanted to spend his last days outside prison.
"I've done enough time," he said. "I'm a different man, and I'm ready to be paroled."
Los Angeles Deputy District Attorney Alexis De la Garza argued for Powell's continued incarceration, saying Powell committed "a cold, deliberate crime."
Powell and Jimmy Lee Smith were convicted of abducting Officers Ian Campbell and Karl Hettinger in Hollywood on March 6, 1963, after being pulled over for making an illegal U-turn.
Powell disarmed the officers by pulling a gun on Campbell and threatening to kill him. Then he and Smith drove them to an onion field near Bakersfield.
Wrongly believing that they had violated the federal kidnapping statute known as the "Lindbergh Law," and faced the death penalty if captured, Powell shot Campbell in the face, killing him.
Hettinger fled as Powell fired at him, running four miles to the safety of a farmhouse.
Powell and Smith, both ex-convicts, were arrested soon after.
Hettinger was haunted by that night and shunned by his colleagues. He left the force, went into the nursery business and later became a Kern County supervisor. He died in 1994 at age 59.
Powell and Smith were originally sentenced to die, but the penalties were reduced to life in prison when the California Supreme Court overturned the state's death penalty. The punishment has since been reinstated, but didn't apply retroactively.
The crimes were documented in 1973's "The Onion Field" and the 1979 film of the same name, both written by Joseph Wambaugh, a former Los Angeles police officer.
"I guess this is the end of the story," Wambaugh said. "They are all gone now. Maybe I'll feel more at peace when I drive by the intersection of Carlos and Gower."
Los Angeles city officials last week dedicated the Hollywood corner as "Ian Campbell Square," named for the officer who died.
Wambaugh said in a 2011 interview with The Associated Press that he visited Powell and Smith in prison when he was writing the book and found their crime inexplicable based on their background.
"They were both smart guys and just petty criminals who got in over their heads one night," Wambaugh said. "Who would have thought two such losers would do such a horrific crime?"
He said when he asked Powell if he had any complaints about the manuscript for "The Onion Field," he had only one.
"He said, 'I don't think I'm nearly as physically unattractive as you seem to think I am" said Wambaugh. "That hurt his vanity."
Powell was portrayed as the leader of the fatal kidnapping plot and was played by James Woods, who had a gaunt and pockmarked face in the film.
Powell tried 11 times for parole. The Los Angeles police union opposed his release each time.
Campbell's daughter appeared at the last parole hearing and said it would be an insult to all police officers if Powell was released.
Wambaugh said that one of Powell's lawyers often complained that "Powell would have been out of prison if it hadn't been for 'The Onion Field' book.
"And I think he was right," Wambaugh said. "The book kept Powell in prison. It just became so famous."
The writer and former officer didn't seem to regret that. "I'm not shedding any tears," he said.
Smith, who was characterized as a follower, was paroled in 1982. He was subsequently arrested numerous times, mostly on drug-related charges.
He died April 7, 2007, of a heart attack at the Pitchess Detention Center in Castaic, where he was being held for failing to report to a parole officer.
In his final days, Powell's daughter came to see him, a prison spokesman said.