Powell was raised in Michigan by a dysfunctional family. His father was a musician who was often absent during his childhood and his mother had health problems, leaving Powell to take care of his three younger siblings. At age 15, Powell ran away from his home and hitchhiked to Florida, where he met a Catholic priest and they had a brief sexual relationship. At age 16, he stole money and a car from his sister; he stole another car when he was 18. Powell served time in Michigan for car theft. When he was 20, Powell was released from prison. At one point in his life, after he and his family moved to California, Powell underwent a craniectomy or a craniotomy at Vacaville Medical Facility to remove a brain tumor. Powell was frequently in and out of prison; by the time he was 29 years old, ten of the last 13 years of his life were spent behind bars. He was officially paroled in May 1962. Powell worked as thief and had often robbed liquor stores. He also worked as a gay hustler. As of January 1963, Powell had been responsible for a series of armed robberies in Las Vegas. At the time of the kidnapping, Powell was residing in Boulder City, Nevada.
Kidnapping of Campbell and Hettinger
At about 10:00 p.m. on March 9, 1963, in Hollywood, Officers Campbell and Hettinger pulled over a 1946 Ford coupe with Nevada license plates at the corner of Carlos Avenue and Gower Street for an illegal U-turn. Present in the vehicle were Powell and his accomplice, Jimmy Lee Smith. According to Powell, "...when the officers stopped our car, we had our guns ready." After Powell was ordered to get out of the car, he disarmed Campbell by pointing a gun at his head and threatened to kill him. Hettinger did not put down his gun until Campbell told him to. With Smith's help, Powell abducted both of the officers and forced Campbell to drive them to an onion field in Bakersfield.
Murder of Campbell and arrest
When they arrived at the onion field, the officers were forced out of the car and ordered to stand with their hands above their heads. Powell asked Campbell, "Have you ever heard of the Little Lindbergh Law?" After Campbell replied, "Yes", he was shot in the face, specifically the mouth. According to Hettinger, it was Powell who shot Campbell on the face; he then told the Los Angeles Times, "I knew I was next. I turned away and ran down the road. When I looked back, they fired at me...." Hettinger successfully managed to escape from Powell and Smith, running to a farmhouse. It is believed that the four other bullets that hit Campbell's chest were fired by both Smith and Powell. However, Powell claimed that Smith fired the four other shots whereas the latter claimed the former fired them. Powell was arrested a few hours later by a CHP officer after attempting to escape via a stolen car. Although Powell was armed at the time of his arrest, he showed no resistance. Smith was arrested the next day.
Conviction and imprisonment
On September 4, 1963, Powell was convicted of the kidnapping of Campbell and Hettinger and of the murder of the former. He was sentenced to death in November that same year.
Retrial and escape attempts
In July 1967, Powell was granted a second trial; once again, he was convicted and sentenced to death. Later that year, Powell unsuccessfully attempted to escape from San Quentin State Prison with three other inmates. In 1968, he attempted to smuggle guns into the Los Angeles County Jail, and in 1969, he attempted to escape its recreation room.
Powell was originally scheduled for parole on June 13, 1982. A petition submitted by the group Citizens for Truth in Justice garnered 31,500 signatures protesting against parole, which led to the rescission of Powell's parole date. The group was assisted in its effort by Powell's victim's daughter, Valerie Campbell. Powell was able to obtain an order of release from Solano County Superior Court Judge Ellis Randall. However, John Mancino, founder of Citizens for Truth, was able to submit a legal brief to the First District Court of Appeals in San Francisco ordering Powell to remain in prison. The case then went to the California Supreme Court, where Mancino and his group prevailed. California Governors George Deukmejian and Jerry Brown were against Powell being released. Powell's lawyer, Dennis Riordan, blamed it on a February 1982 TV airing of The Onion Field. Between 1982 and 2010, Powell had been denied parole 11 times. Powell had worked as a clerk in the law library at the Mule Creek State Prison in Ione, California. By 1994, Powell was incarcerated at Deuel Vocational Institution. In 2011, Powell had also been denied compassionate release despite a diagnosis of terminal prostate cancer.
Reaction to ''The Onion Field''
Joseph Wambaugh, author of The Onion Field, interviewed Powell while he was in prison. According to Wambaugh, Powell had only one complaint about the book, "that he thought he was more physically attractive than I portrayed him to be." Wambaugh also confirmed that one of Powell's lawyers claimed Powell would have been released from prison had it not been for the book or its film adaptation.
Media portrayal
Powell was portrayed by actor James Woods in the 1979 film The Onion Field. Woods did not meet with Powell when preparing for his role. Woods was nominated for a Golden Globe for his performance in the film.
Death
On August 12, 2012, Powell died of prostate cancer at the California Medical Facility in Vacaville, California. He was 79 years old. His death occurred two days after a Hollywood intersection was dedicated in Officer Ian Campbell's name. Tyler Izen, president of the Los Angeles Police Protective League, issued a statement: "Gregory Powell was a cold-blooded murderer who avoided the death penalty, but he won't escape God's judgment. While Officer Ian Campbell can never be brought back, nor the damage and heartache caused by Powell and Smith be undone, justice was upheld when the parole board denied Powell's request for compassionate release and ensured he drew his last breath while confined behind prison bars."
