Gregory Powell, who was convicted of kidnapping and killing a Los Angeles police officer in 1963, a brutal crime that inspired the popular book and film “The Onion Field,” died on Sunday in a prison hospital in Vacaville, Calif. He was 79.
He died of natural causes, the California Department of Corrections and Rehabilitation said.
Mr. Powell was a career thief who had robbed a series of liquor stores before March 9, 1963, when he and a regular accomplice, Jimmy Lee Smith, were stopped by two plainclothes policemen for making an illegal U-turn. Mr. Powell and Mr. Smith were armed.
Mr. Powell pointed his weapon at Officer Ian J. Campbell and ordered the second officer, Karl Hettinger, to give his gun to Mr. Smith. The robbers then forced the officers to get in the car and drove outside the city. They eventually stopped in an onion field near Bakersfield, Calif. There, Mr. Powell fatally shot Officer Campbell in the face. Just after the killing, Officer Hettinger began running away and escaped.
Both defendants were sentenced to death, but the sentences were reduced to life terms after California abolished capital punishment. (It was later reinstated.)
Joseph Wambaugh, the author of the 1973 book “The Onion Field” and the screenplay for the 1979 film of the same name, was a detective working in a nearby station in Los Angeles at the time of the killing. When Officer Hettinger returned to work, he was viewed as a failure in the department, and Mr. Wambaugh became fascinated by the struggles he faced.
“He was a troubled man,” Mr. Wambaugh said in an interview on Monday. “In 1963, the world didn’t know much about post-traumatic stress syndrome, certainly as it applied to the police service.”
Mr. Wambaugh interviewed Mr. Powell and Mr. Smith extensively in prison.
“The only complaint Powell ever made about the book after he read it was that he thought he was more physically attractive than I portrayed him to be,” Mr. Wambaugh said.
Mr. Smith was particularly helpful to Mr. Wambaugh in his research, sharing a memoir he had written. Mr. Smith was granted parole in 1983 but returned to prison after multiple parole violations, often on drug-related crimes. He died in prison in 2007.
Officer Hettinger died of liver cancer in 1994.
Mr. Powell sought parole on multiple occasions over the years but never received it. He was denied most recently in 2010.
In the movie, Mr. Powell was played by James Woods, Mr. Smith by Franklyn Seales, Officer Hittinger by John Savage, and Officer Campbell by Ted Danson.
“His lawyer often maintained that the only reason Powell was kept in prison all of those years was because of the notoriety he received from my book and my film,” Mr. Wambaugh said. “Well, for that I have no apology.”
This article has been revised to reflect the following correction:
Correction: August 21, 2012
An earlier version referred imprecisely to capital punishment in California. While the death sentences that Mr. Powell and his co-defendant, Jimmy Lee Smith, received were âreduced to life terms after California abolished capital punishment,â the state later reinstated the death penalty.