The Grondalski family murders by the Hells Angels occurred on October 5, 1986, in Mendocino County, California, in the United States.
Background
William "Billy" Grondalski was a worker at an oil refinery in Martinez and a "wrencher" (slang for a mechanic). He married Patricia "Patty" Kast, a receptionist at a beauty salon who had a teenage son, Jeremy, from a previous marriage. Together, the couple had a daughter, Dallas, born in 1981. In 1982, Billy Grondalski joined the Vallejo chapter of the Hells Angels. The working class Grondalski seems to have joined the Hells Angels out of the belief that it would make him into a wealthy man. Instead, Grondalski engaged in substance abuse as he drank heavily and became addicted to methamphetamine. Grondalski had a tattoo of the Hells Angels death's head logo on his arm. A number of Hells Angels frequently visited the Grondalski household and knew the Grondalski children well, most notably Charles "Chuck" Diaz. Debroah "Debbie" Kast, the sister of Patty, recalled about Dallas: "She was just a smart little girl for her age." In 1985, Patty Grondalski filed for divorce under the grounds that her husband spent more time with the Hells Angels than with her.
In April 1986, a Hells Angel from the Oakland chapter, Terry Dalton, was expelled for stealing, and Sonny Barger, the Angels leader, forbade the Angels from having any social contact with him. On May 14, 1986, Barger issued a photograph of Dalton to Hells Angel chapters saying that Dalton had been expelled and some of the chapters, especially the Vallejo chapter, were "fucking up" by continuing to talk to Dalton. In July 1986, Barger summoned the entire Vallejo chapter to the clubhouse of his Oakland chapter where the Vallejo chapter president, Derrick Kualapi, and several others were beaten for continuing to talk to Dalton. Grondalski seems to have been horrified about the beatings he witnessed. Grondalski had maintained ties with Dalton and was selling drugs on the territories of other Angels, which led him to fear that he likewise might be beaten or worse. After the witnessing the beatings, Billy Grondalski told his estranged wife that he wished to leave the Angels, which led to a reconciliation. Billy told his estranged wife while she was visiting her father in the hospital "I'm out of the club", which led her to say "I'm so glad". Grondalski showed her a new tattoo he added under his Hells Angels death's head tattoo reading "84 In 86 Out". On August 21, 1986, Barger appointed Gerry "Butch" Lester as the new president of the Vallejo chapter. On September 27, 1986, Lester reported to Barger: "Billy has, uh, since become the, uh, in bad standing. Tattoos need to be covered, and notify Vallejo if anybody sees him. We wanna talk to him, and that's it basically". The fact that Grondalski had not covered his Hells Angels tattoos up after leaving was a source of much rage in the Hells Angels. Patty told her sister Debbie that she was afraid for her life as she told her "It's not over. It's not".
The Grondalski family lived like fugitives, and moved to a new house in Fort Bragg on October 1, 1986. Most notably, Billy and Patty only moved their furniture at night. Debbie Kast, the sister of Patty, noted that Billy "seemed nervous" the last time she saw him on October 4, 1986 during a visit to her house. Later that evening, Billy received a phone call and suddenly said: "Come on, we're getting out of here!" On the same day, the Hells Angels were holding a run in Sonoma County where two Hells Angels, Gerry "Butch" Lester and Charles "Chuck" Diaz, borrowed a truck from another Angel, Michael "Little Mike" Tankersley. Lester and Diaz stated that they needed a vehicle to go to Fort Bragg as Grondalski had been found. Tankersley was a man with a long criminal record for assault. Another Hells Angel present at the run was Charlie Haas, who just returned from Germany where he had served eight years in prison for stabbing a man to death. The Hells Angels were angry at Grondalski for still wearing his Hells Angels tattoos despite having left the club "in bad standing".
The massacre
At 10:23 am on October 5, 1986, Billy purchased some fishing gear and light bulbs from a Payless store and then returned home. The purchased products were found in his car by the police. Lester and Diaz arrived at Grondalski house shortly after he returned home. Lester pointed a .45 pistol at Billy and claimed that the gun accidentally went off. Billy took a bullet straight though the head, killing him instantly in his kitchen.