Angelo Anthony Buono Jr. (October 5, 1934 – September 21, 2002) was an American serial killer, kidnapper and rapist, who together with his cousin Kenneth Bianchi were known as the Hillside Stranglers, and were convicted of killing ten young women in Los Angeles, California between October 1977 and February 1978.

Angelo Buono was born on October 5, 1934, in Rochester, New York to first-generation Italian emigrants from San Buono. Buono had developed an extensive criminal history, ranging from failure to pay child support, grand theft auto, assault and rape. In 1975, when Buono was 41 years old, he came into contact with his cousin, Kenneth Bianchi.^[1] A self-described "ladies man", Buono persuaded Bianchi to join him in prostituting two women he had been holding as virtual prisoners.

In October 1977, Buono and Bianchi began killing women, cruising around Los Angeles, California in Buono's car and using fake badges, persuaded women they were undercover police officers. They would then order the victims into Buono's car, which they claimed was an unmarked police car, and drive to Buono's home to torture and murder them. The women and girls ranged in age from 12 to 28. The victims were:

Both Buono and Bianchi would sexually abuse their victims before strangling them. They experimented with other methods of killing, such as lethal injection, electric shock, and carbon monoxide poisoning. Even while committing the murders, Bianchi applied for a job with the Los Angeles Police Department (LAPD) and had even been taken for several rides with police officers while they were searching for the Hillside Stranglers. Shortly after they botched their would-be eleventh murder, Bianchi revealed to Buono he had participated in LAPD police ride-alongs, and that he was currently being questioned about the Hillside Strangler case. Buono flew into a rage and threatened to kill Bianchi if he did not move to Bellingham, Washington. In May 1978, Bianchi moved to Bellingham.

The legal case against Buono was based largely upon Bianchi's testimony. Deciding that Bianchi was an unreliable and uncooperative witness, the case's original prosecutors from District Attorney John Van de Kamp's office moved to dismiss all charges against Buono and set him free. The presiding judge, Ronald M. George, refused to release Buono and reassigned the case to California Attorney General George Deukmejian's office. Buono's trial would become the longest in American legal history, lasting from November 1981 until November 1983. During the trial, Bianchi, in exchange for a lighter sentence, testified against Buono. The jury convicted Buono on nine counts of murder and sentenced him to life imprisonment, with Judge George commenting that he felt a death sentence would have been the appropriate punishment.

In 1986, Buono married Christine Kizuka, a mother of three and a supervisor at the California State Employment Development Department.^[2] He died in September 2002. ^[3] His body was cremated.^[4]

In 2007, Buono's grandson, Christopher Buono, committed suicide shortly after shooting his grandmother, Mary Castillo, in the head. Castillo was at one time married to Buono, and had five children with him, including Chris' father.^[5][6] Chris Buono was unaware of his grandfather's true identity until 2005.

In the 1989 film The Case of the Hillside Stranglers, Buono was portrayed by actor Dennis Farina.^[7] In the 2004 film The Hillside Strangler, Buono was portrayed by actor Nicholas Turturro and in Rampage: The Hillside Strangler Murders (2006), he was played by Tomas Arana.