American mass murderers

John Felton Parish (July 4, 1933 – August 9, 1982) was an American spree killer who shot dead six people and wounded three others at two warehouses in Grand Prairie, Texas, United States on August 9, 1982. Afterwards, while driving a hijacked semi-trailer truck, he led police on a high-speed chase through Grand Prairie downtown that ended only when he broke through a police barricade, injuring an officer, and crashed into a building. He was subsequently killed by police during a shootout.It was the worst shooting rampage in Dallas-Fort Worth history at that time.

Gary Lee Sampson (September 29, 1959 – December 21, 2021) was an American bank robber and later spree killer who killed three people and was sentenced to death by a federal jury in Massachusetts.
During three days in 2001, Sampson killed three strangers – retiree Philip McCloskey in Marshfield, Massachusetts, college student Jonathan Rizzo in Abington, Massachusetts, and Robert Whitney in Meredith, New Hampshire. He also attempted to kill a fourth victim and stranger, William Gregory, in Plymouth, Vermont. Sampson killed McCloskey and Rizzo after they picked him up hitch-hiking, stabbing them to death. Shortly after that he strangled Whitney. Sampson pleaded guilty to the three killings on September 9, 2003, and was sentenced to death on December 23, 2003, by a federal jury in Massachusetts. He received the death penalty for the two Massachusetts killings, and a life sentence for the New Hampshire case.After Sampson pleaded guilty, a federal jury decided whether he should be sentenced to death or life in prison. The defense introduced mental health experts to testify that Sampson had dyslexia as a child, had bipolar disorder, and "suffered from a significant mental impairment" during the killings. A psychiatrist called by the government testified that Sampson did not have any mitigating mental impairment; he was intelligent but violent and deeply antisocial, with antisocial personality disorder. The jury of 12 unanimously returned a sentence of death.
In 2011, Sampson's death sentence was thrown out due to juror misconduct, and he was scheduled for a second sentencing trial on September 16, 2015. He was again sentenced to death on January 9, 2017. He died in 2021 at the age of 62, presumably from end stage liver disease.

John C. Salvi III (March 2, 1972 – November 29, 1996) was an anti-abortion extremist who carried out fatal shootings at two abortion facilities in Brookline, Massachusetts on December 30, 1994. The shootings killed two and wounded five. An insanity defense at his trial was not successful and he was convicted of two counts of murder and sentenced to life in prison without the possibility of parole. He died in 1996 in what was officially ruled a suicide in his jail cell.

Herbert William Mullin (April 18, 1947 – August 18, 2022) was an American serial killer who killed 13 people in California in the early 1970s. He confessed to the killings, which he claimed prevented earthquakes. In 1973, after a trial to determine whether he was legally insane or culpable, he was convicted of two murders in the first-degree and nine in the second-degree, and sentenced to life imprisonment. During his imprisonment, he was denied parole eight times.Mullin and Edmund Kemper overlapped in their 1972 to 1973 murder sprees, adding confusion to the police investigations and ending with both being arrested, within a few weeks of each other, after the deaths of 21 people.

Caril Ann Fugate (born July 30, 1943) is the youngest female in United States history to have been tried and convicted of first-degree murder. She was the adolescent girlfriend of spree killer Charles Starkweather, being just 14 years old when his murders took place in 1958. She was convicted as his accomplice and sentenced to life imprisonment. In 1976, she was paroled after serving 18 years.