Hettinger was born in Los Angeles, California to Francis and Elsie Hettinger. He had two sisters, Miriam and Eunice. He was raised in Los Angeles. He was married to Helen Beth Davis in Las Vegas, Nevada on May 1, 1962; they had three children: Laurie, Kurt and Christine. On the night of March 9, 1963, Hettinger and his partner, Ian Campbell, pulled over a vehicle driven by Powell and Smith. After both men got out of the vehicle, Powell disarmed Campbell and pointed a gun at his back. Smith and Powell held the officers hostage and all four of them returned to the vehicle. Campbell was then forced to drive the four of them to an onion field near Bakersfield. When they arrived, the officers were ordered to step out into the field. Powell asked Campbell if he had ever heard of the Lindbergh Law. When Campbell replied "Yes," Powell shot him. Hettinger managed to escape to a farmhouse where he called for help. Powell was arrested hours later whereas Smith was arrested the next day. According to Pierce Brooks, the officer who investigated the crime, Hettinger suffered from survivor's guilt because of Campbell's death, describing it as a "tremendous guilt complex." Depressed and finding it difficult to function, Hettinger was transferred to a less stressful job, as a driver for the police chief. But after he began shoplifting, Hettinger was forced to resign from the police department. In addition, Hettinger was forced to visit squad rooms and publicly admit blame for his lack of courage at the onion field. His experience inspired the controversial "Hettinger Memorandum," whereby officers were admonished never to give up their weapons. Joseph Wambaugh said of Hettinger after writing both the book and the film about the "Onion Field" incident, "Karl minded terribly, but I just exploited him. I used money as my weapon to get the story, I offered him money that for the sake of his family he couldn't refuse. I acted that way because I thought the story was more important than Karl Hettinger, more important than me -- that it was a story so important that I would have done almost anything to get it written." In 1985, Hettinger spoke for the first time about the incident: "I still get uneasy. I still can't sleep very well. I can still see their faces. I want to stop him from getting back on the street. I know this man." That same year, Hettinger strongly opposed parole for Powell. Hettinger said, "I'm speaking as a victim. A very good friend of mine was murdered and the same men tried to murder me. But the death penalty was not carried out. I don't think it's right. I've been quiet too long." In 1987, Hettinger was appointed by California Governor George Deukmejian to the Kern County Board of Supervisors. Hettinger died on May 4, 1994 at a hospital in Bakersfield. He was 59. The cause of death was liver failure.
