American mass murderers

Eric David Harris (April 9, 1981 – April 20, 1999) and Dylan Bennet Klebold ( KLEE-bohld; September 11, 1981 – April 20, 1999) were American high school seniors who perpetrated the Columbine High School massacre at Columbine High School on April 20, 1999 in Columbine, Colorado. Harris and Klebold killed 12 students, one teacher, and wounded 24 others. After killing most of their victims in the school's library, they died by self-inflicted gunshot wounds. At the time, it was the deadliest high school shooting in U.S. history.The ensuing media frenzy and moral panic led to "Columbine" becoming a byword for school shootings, and becoming one of the most infamous mass shootings ever perpetrated in the United States.Harris and Klebold were both born in 1981. Harris was born in Wichita, Kansas, but moved around frequently as a child due to his father's occupation in the United States Air Force, while Klebold was born and raised near Columbine. Harris's family eventually settled in Colorado in 1992. Shortly after, Harris and Klebold met while they were in the 7th grade. Over time, they became increasingly close. By the time they were juniors in high school, they were described as inseparable. There are differing reports; some say Harris and Klebold were very unpopular students once they were upperclassmen, as well as frequent targets of bullying, while others say they were not near the bottom of the school's social hierarchy and that each had many friends, along with active social lives. Columbine High School was known to have an intense "jock culture", which saw popular students, mainly athletes, benefit from special treatment from faculty and other students.According to their journal entries, Harris and Klebold had seemed to begin planning the attack by May 1998, nearly a year before the attack. Throughout the next eleven months, Harris and Klebold meticulously built explosives and gathered an arsenal of weapons. Both Harris and Klebold each left behind several journal writings and home videos, ones they made both alone and together, foreshadowing the massacre and explaining their motives. Harris and Klebold hoped this content would be viewed by the public extensively and inspire followers, although much of the evidence has never been released by authorities.
Harris and Klebold often wore trench coats in school, and in general, as part of their everyday outfits, so after the massacre, it was widely believed Harris and Klebold were part of a clique in school called the "Trenchcoat Mafia", a group of misfits in the school who supposedly rebelled against the popular students. This turned out to be untrue, as neither Harris nor Klebold had any affiliation with the group. The pair's aforementioned writings and videos gave insight into their rationale for the shooting. The FBI concluded that Harris was a psychopath, who exhibited narcissistic traits, unconstrained aggression, and a lack of empathy, while Klebold was concluded to be an angry depressive with a vengeful attitude toward individuals who he believed had mistreated him. However, neither Harris nor Klebold were formally diagnosed with any personality disorders prior to the attack, so this conclusion is often debated. In the following years, various media outlets attributed multiple motivating factors to the attack, including bullying, mental illness, racism, psychiatric medication, and violence in music, movies, and video games. Despite these conclusions, the exact motive for the attack remains inconclusive.
Harris and Klebold have become pop culture icons, with the pair often portrayed, referenced and seen in film, television, video games, music and books. Many killers since the shooting have taken inspiration from the pair (dubbed the Columbine effect), either hailing them as heroes, martyrs and gods, or expressing sympathy for them. Harris and Klebold also have a fanbase, who have coined the term "Columbiners", who write fan fiction and draw fan art of them. Others have also dressed as the duo for cosplay or Halloween.

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.