"Onion Field" killer Jimmy Smith was initially released in 1982, but returned to prison several times on drug-related parole violations. In December 2006, he failed to report to his parole officer and a warrant was issued for his arrest. In February 2007, a man matching Smith's description was detained by police in Los Angeles' Skid Row area and eventually identified as Smith. He was arrested and charged with violating his parole, and sent to the Pitchess Detention Center in Castaic, California. On April 7, 2007, while in that facility, he died of an apparent heart attack at age 76.
Gregory Powell's parole-board hearing on January 27, 2010, he was denied parole. In a January 21, 2010 letter to state corrections officials, L.A. police union President Paul Weber urged the board to deny parole, calling Powell a "vicious murderer who has not yet paid his debt to society." On October 18, 2011, the California State Parole Board denied compassionate release for Powell, who had been diagnosed with terminal prostate cancer. The board stated that Powell did not wish to be released from prison and was likely to be uncooperative if paroled. Powell died on August 12, 2012, at the California Medical Facility in Vacaville. He was 79 years old.)
On March 9, 1963, LAPD officers Campbell and Karl Hettinger pulled over a car containing two suspicious-looking men on a Hollywood street. The two men, Jimmy Lee Smith (aka "Jimmy Youngblood") and Gregory Ulas Powell, had recently committed a string of robberies. Powell, the driver, pulled a gun on Campbell and ordered Hettinger to surrender his gun to Smith. The two officers were then forced into Powell's car and driven to an onion field around Bakersfield where Campbell was fatally shot. Hettinger was able to escape, running nearly four miles to reach a farmhouse. The killing occurred primarily because Powell assumed that the kidnapping of the officers alone constituted a capital crime under the state's Little Lindbergh Law. However, Powell's interpretation was incorrect, as under the Little Lindbergh Law kidnapping became a capital crime only if the victim was harmed. (Today, kidnapping in California, where there is bodily harm short of death, is punishable either by imprisonment for 25-years-to-life, or by life imprisonment without the possibility of parole.)
Powell was arrested on the night of the murder. The following day, Smith was apprehended as well. The lead LAPD investigator on the case was Sergeant Pierce Brooks. Both suspects, convicted of murder and sentenced to death, ultimately received life-imprisonment sentences following a court decision that for a period abolished executions in California.
Though Hettinger was able to escape, he was scorned by his fellow officers and suffered severe emotional trauma for both the initial incident and following fellow treatment. Eventually a police training video was made using his experience as example of what not to do when stopping and approaching a vehicle.
Hettinger was forced to resign from the LAPD in 1966 after being accused of several acts of petty theft and abusing alcohol. Years later, Hettinger was appointed to serve as a Kern County Supervisor for Bakersfield, CA where he served multiple consecutive terms. He was later divorced and died of a liver disease in 1994 at the age of 59.
The book was adapted into an eponymous 1979 film directed by Harold Becker. It starred John Savage, James Woods, Franklyn Seales and Ted Danson.