Kenneth Alessio Bianchi is an American serial killer, kidnapper, and rapist. He is known for the Hillside Strangler murders committed with his cousin Angelo Buono Jr. in Los Angeles, California, as well as for murdering two more women in Washington by himself. Bianchi is currently serving a sentence of life imprisonment in Washington State Penitentiary for these crimes. Bianchi was also at one time a suspect in the Alphabet murders, three unsolved murders in his home city of Rochester, New York, from 1971 to 1973.

A serial killer is a person who murders three or more people, with the killings taking place over a significant period of time between them. The serial killers' psychological gratification is the motivation for the killings, and many serial murders involve sexual contact with the victims at different points during the murder process. The Federal Bureau of Investigation (FBI) states that the motives of serial killers can include anger, thrill-seeking, financial gain, and attention seeking, and killings may be executed as such. The victims tend to have things in common such as, demographic profile, appearance, gender or race. The FBI will focus on particular patterns that the serial killers follow throughout their murders. They will then use on the patterns they find for key clues into finding the killer along with their motives. Although a serial killer is a distinct classification that differs from that of a mass murderer, spree killer, or contract killer, there are overlaps between them.