(CNN) Here's a select list of convicted American serial killers and notable open or unsolved cases.
Serial murder is defined by the FBI as two or more killings separated by a span of time.
Serial murders are relatively rare. Fewer than one percent of homicides during a given year are committed by serial killers, the FBI reports.
Nickname: Son of Sam
Number of confirmed victims: 6
Years and location: 1970s, New York City
Characteristics: Initially claimed a neighbor's dog was possessed by an ancient spirit that commanded him to shoot people. The dog owner's name was Sam. Berkowitz later said the dog story was a hoax.
Arrest, conviction and sentence: Arrested on August 10, 1977. Pleaded guilty to murdering six people and sentenced to 25-years-to-life for each murder. Currently incarcerated at the Shawangunk Correctional Facility in upstate New York.
Number of confirmed victims: Unknown, confessed to more than two dozen murders before he was executed but he may have been linked to additional slayings.
Years and locations: 1970s, multiple states including Washington, Utah, Colorado and Florida
Characteristics: Preyed on young women and sometimes lured victims by pretending to be injured. Bundy had studied psychology in college, worked as a suicide hotline volunteer while at school and served at one point as assistant director of the Seattle Crime Prevention Advisory Commission.
Arrest, conviction and sentence: Arrested for the final time on February 15, 1978. He had been previously arrested for murder in Colorado but escaped from custody, before being captured in Aspen a few days later. Months later, Bundy escaped again, prompting a nationwide manhunt. While a fugitive in Florida, he killed two college students and a 12-year-old girl. Bundy was apprehended a third and final time in Pensacola in a stolen car. He was convicted on three counts of murder and sentenced to death in the electric chair. Executed on January 24, 1989.
Nicknames: The Hillside Stranglers
Number of confirmed victims: At least 9
Years and locations: 1970s, Los Angeles, Washington state
Characteristics: Buono and Bianchi were cousins who posed as police officers to trap teenage girls and young women, some of whom worked as prostitutes. Bianchi claimed that he suffered from multiple personality disorder but later admitted that he faked the condition. Buono owned an auto upholstery shop and was not a suspect until Bianchi was caught, confessed and identified his cousin as his accomplice.
Arrest, conviction and sentence: Bianchi was arrested on January 12, 1979; Buono was arrested on October 19, 1979. Bianchi was arrested in Bellingham, Washington, as a suspect in the murders of two college students at Western Washington University. He pleaded guilty to the slayings in Washington and confessed to five of the Los Angeles murders. He was sentenced to five life terms for murder and one additional life sentence for conspiracy. Bianchi is incarcerated at the Washington State Penitentiary in Walla Walla. Buono was arrested at his home in Glendale, California, the same day Bianchi admitted he participated in five of the Hillside killings. Bianchi testified during Buono's trial. Buono was convicted of nine murders and was sentenced to life in prison without the possibility of parole. He died in prison in 2002.
Number of confirmed victims: 25
Year and location: 1971, Yuba City, California
Characteristics: A farm labor contractor, Corona was convicted in the stabbing deaths of 24 workers. His 25th victim was shot. During a 2011 parole hearing, he confessed to killing the men. Corona, who was 77 and suffering from dementia at the time of the hearing, described his victims as alcoholics who had trespassed in the orchards.
Arrest, conviction and sentence: Arrested on May 26, 1971. Corona was arrested after a neighbor reported suspicious activity in a peach orchard. Police found 25 bodies buried in shallow graves in orchards surrounding the Feather River and traced the bodies to Corona. Four victims were never identified. After being convicted in 1973, Corona was sentenced to 25 life terms in prison but an appeal led to a new trial in 1982. Corona was again convicted at the second trial and sentenced to 25 concurrent terms of 25-years to life. He died of natural causes on March 4, 2019.
Number of confirmed victims: 16 (Dahmer confessed to 17 murders but prosecutors lacked evidence to convict him in the additional killing)
Years and locations: 1970s-1990s, primarily in the Milwaukee area
Characteristics: A former chocolate factory worker, Dahmer picked up young men at bus stations, bars, shopping centers and other locations. He got them to visit his apartment by offering them money to pose for photos or by promising them alcohol. He drugged them and strangled them. He ate parts of at least one of his victims and kept the remains of others in his apartment.
Arrest, conviction and sentence: Arrested on July 22, 1991. Dahmer was apprehended after one of his captives escaped and went to the police, still wearing handcuffs Dahmer shackled to one of his wrists. Charged with 15 counts of murder, he pleaded guilty but insane. A Milwaukee jury ruled against Dahmer's insanity claim, and he was sentenced to 15 life terms in February 1992. Dahmer pleaded guilty to a 16th murder in Ohio and was sentenced to an additional life term in May 1992. He was beaten to death in prison in 1994.
Nicknames: The Golden State Killer, Visalia Ransacker, East Area Rapist, Original Night Stalker
Number of confirmed victims: At least 13
Years and location: 1970s-1980s, California
Characteristics: DeAngelo, a former police officer, began with a string of burglaries, then grew more violent with a series of killings, rapes and assaults in the 1970s and 1980s, as he moved from one county to the next. Two of his earliest known homicides were the murders of a couple in Rancho Cordova who may have witnessed him breaking into a home. After the Rancho Cordova slayings, DeAngelo started a series of murders in the Santa Barbara area, more than 300 miles south of Sacramento. Investigators at the time didn't see a connection between the attacks in Santa Barbara and Sacramento. Decades after the killings, true crime author Michelle McNamara drew attention to the case with blog posts and a book, "I'll Be Gone in the Dark," published two years after her sudden death in 2016.
Arrest, guilty plea and sentence: DeAngelo was arrested on April 24, 2018. Detectives used a public genealogy website to narrow down their list of suspects and then collected DNA samples from DeAngelo's trash and the door handle of his car. Hours after they confirmed two DNA matches, DeAngelo was arrested. On June 29, 2020, DeAngelo pleaded guilty to 13 counts of first-degree murder and special circumstances -- including murder committed during burglaries and rapes -- as well as 13 counts of kidnapping, and he acknowledged more than 50 rapes he was not charged for because of California's statute of limitations. DeAngelo avoids the death penalty with his guilty plea. On August 21, 2020, DeAngelo was given 11 life sentences without the possibility of parole.
Nickname: The Grim Sleeper
Number of confirmed victims: 10
Years and location: 1980s-2000s, Los Angeles
Characteristics: Franklin targeted prostitutes and female drug addicts. Franklin was called the Grim Sleeper because he was believed to have stopped killing for more than a decade before he began a second murder spree during the 2000s. Franklin, a married father of two, is a former city sanitation worker and garage attendant.
Arrest, conviction and sentence: Arrested on July 7, 2010. Undercover Los Angeles police officers obtained a sample of Franklin's DNA from a leftover pizza slice and matched it to the killer's DNA. He was convicted of slaying 10 people and was sentenced to death in 2016. He died in prison in 2020.
Number of confirmed victims: 33
Years and locations: 1970s, Chicago area
Characteristics: A construction company owner who moonlighted as a children's party clown, Gacy abducted young men and boys or lured them to his home. He was twice married and divorced with two children.
Arrest, conviction and sentence: Arrested on December 21, 1978. Police investigating the disappearance of a teenage boy discovered the remains of victims in a crawlspace under Gacy's house. He was sentenced to death by lethal injection on 33 counts of murder. Executed on May 10, 1994. In 2011, Sheriff Tom Dart and the Cook County Sheriff's Office began to identify the last eight unnamed victims of Gacy. As of October 2021, only 5 remain unidentified.
Number of confirmed victims: Convicted of 16 murders in Orange County, California but linked to at least 29 additional slayings nationwide, according to prosecutors. Detectives found a notebook in Kraft's briefcase that contained a list with more than 60 entries. Prosecutors said the journal chronicled Kraft's killings. Defense attorneys argued the diary included ambiguous entries like "New Year's Eve," referencing events unrelated to murder.
Years and locations: 1970s-1980s, California, Oregon, Michigan
Characteristics: Kraft, a computer consultant, picked up young hitchhikers on the interstate. He targeted men with military backgrounds.
Arrest, conviction and sentence: Arrested on May 14, 1983. Kraft was pulled over by California Highway Patrol for weaving, and officers found a dead body in the front passenger seat. He was convicted on 16 murder counts and sentenced to death. He is incarcerated awaiting execution at San Quentin State Prison.
Number of confirmed victims: Convicted of eight murders. In 2018, Little confessed to a total of 93 murders during an interview with FBI crime analysts and James Holland of the Texas Rangers. Investigators have confirmed at least 60 of the confessed killings. The FBI describes him as America's most prolific serial killer and has asked for the public's help in identifying more of his victims.
Years and locations: 1970s-2005, Arizona, Arkansas, California, Florida, Georgia, Illinois, Kentucky, Louisiana, Maryland, Mississippi, Nevada, New Mexico, Ohio, South Carolina, Tennessee, Texas
Characteristics: A nomadic drifter, Little began traveling state-to-state and committing crimes after leaving Ohio in the late 1950s. Little often targeted vulnerable women involved in prostitution and addicted to drugs. A one-time competitive boxer, Little would punch and stun his victims before strangling them. Without bullet wounds or stab marks, most of these deaths were attributed to accidents or drug overdoses.
Arrest, conviction and sentence: Arrested on September 5, 2012, at a Kentucky homeless shelter. Little was extradited to California on a narcotics charge. Once Little was in custody, the Los Angeles Police Department matched Little's DNA to victims in three unsolved homicides from 1987 and 1989. He was indicted on three counts of murder, and in 2014, he was convicted and sentenced to three life sentences with no possibility of parole. In 2018, Little was extradited to Texas where he plead guilty to the 1994 murder of Denise Christie Brothers and given a life sentence. In 2019, Little received four additional sentences of life for the murders of four women in Ohio. Little died in prison in 2020.
Nickname: The BTK Killer
Number of confirmed victims: At least 10
Years and location: Kansas, 1970s-1990s
Characteristics: A churchgoer, Cub Scout leader and married father of two, Rader worked at the home security company, ADT, and he later became a code compliance supervisor in suburban Park City, Kansas. Two of his earliest victims were women who worked at an office with him. He also murdered a co-worker's husband and two children. In a letter found folded into a book at the public library that was found months after the first killings, Rader described one of the crime scenes and suggested that he should be called "BTK," short for "bind, torture, kill." He continued mailing cryptic letters to the media and the police prior to his arrest.
Arrest, conviction and sentence: Arrested on February 25, 2005. Rader was caught after he sent a floppy disk to a TV station in response to reports speculating that BTK was dead or in jail because it had been more than a decade since his last victim was found. Police traced the disk to a computer at Rader's church and found that his DNA matched the killer's. Rader pleaded guilty to 10 murders and was sentenced to 10 consecutive life terms. He is currently incarcerated at the El Dorado Correctional Facility in Kansas.
Nickname: The Night Stalker
Number of confirmed victims: Convicted of 13 murders but linked to one additional slaying via DNA.
Years and location: 1980s, California
Characteristics: A drifter with an interest in Satanism, Ramirez typically broke into homes through unlocked windows and doors late at night, shooting any men he encountered while looking for women to attack. His victims ranged in age from nine to 83.
Arrest, conviction and sentence: Arrested on August 31, 1985. Ramirez was captured and held by a mob of citizens in Los Angeles before police intervened and arrested him. He was sentenced to death on 13 counts of murder and was later linked via DNA to a killing in San Francisco. He died of complications from cancer while awaiting execution at San Quentin State Prison in 2013.
Nickname: The Green River Killer
Number of confirmed victims: At least 49
Years and location: 1980s-1990s, Washington state
Characteristics: Ridgway targeted young women who were runaways or prostitutes and left some of the bodies in or near the Green River, a waterway in the Seattle area. He was a thrice married truck painter who had a son with one of his wives. Ridgway was questioned by police in 1983, soon after the killings began, and detectives obtained a search warrant in 1987. At the time, no evidence was recovered linking him to the murders, and he had passed a polygraph test early in the investigation.
Arrest, conviction and sentence: Arrested on November 30, 2001. Advances in DNA testing technology led to the arrest, as law enforcement re-tested evidence that had been collected years before. They found a match and he was charged and taken into custody. He confessed and plead guilty to 48 killings. In 2011, he was charged with a 49th slaying. Ridgway is serving a life sentence at the Washington State Penitentiary.
Number of confirmed victims: Convicted of nine murders but confessed to 17 killings
Years and location: 1990s, New York
Characteristics: An unemployed landscaper who lived with his mother on Long Island, Rifkin would drive to New York City and pick up prostitutes. He strangled his victims and took personal belongings from the women. These items were found in his bedroom, where police also discovered a book about the Green River Killer. His mother claimed that she did not go into her son's bedroom and was unaware of the killings.
Arrest, conviction and sentence: Arrested on June 28, 1993. Rifkin was pulled over for driving without a license plate, and police found a dead woman in the back of his truck. While in custody, he confessed to killing 17 women. During multiple trials, Rifkin's attorneys argued that he suffered from mental illness, but he was convicted on nine charges of murder and was sentenced to more than 200 years in prison. Currently incarcerated at the Clinton Correctional Facility in New York.
Number of confirmed victims: 11
Years and location: 2000s, Ohio
Characteristics: A convicted sex offender, Sowell preyed on women struggling with drug abuse and homelessness. He would invite victims to his house and offer them beer. He told police that he became enraged with the women because they reminded him of an ex-girlfriend who abandoned him after he helped her kick drugs. The victims were strangled and buried on his property.
Arrest, conviction and sentence: Arrested on October 31, 2009. Police issued a warrant for Sowell's arrest after a woman told them that he had hit her and sexually assaulted her. Officers found two bodies in the house and discovered more remains in the backyard. After a 25-day trial, Sowell was convicted of 11 murders and sentenced to death by lethal injection. Sowell died in prison in 2021.
Number of confirmed victims: At least 14, including a pregnant woman
Years and location: 1980s-1990s, Los Angeles
Characteristics: A father of four whose jobs included delivering pizza, Turner targeted female drug users in South Los Angeles.
Arrest, conviction and sentence: Turner was charged with murder in 2004 while incarcerated for rape. Detectives had discovered that his DNA matched a sample from a crime scene and ultimately forensics connected him to 10 killings. During the investigation, police discovered that they had wrongfully convicted an intellectually disabled janitor named David Allen Jones, who served nine years in prison for three of Turner's slayings before he was released in 2004. Turner was convicted of 10 murders in 2007 and sentenced to death. In 2014, he was convicted of four additional murders and again sentenced to death. He is incarcerated at San Quentin State Prison awaiting execution.
Number of confirmed victims: 6 (was linked to at least one other death but the body was never recovered)
Years and location: Florida, 1989-1990
Characteristics: Wuornos had a long history of robbery, prostitution and drug abuse before she began killing men she met along Interstate 75 in Florida. She claimed that over the years, she had been repeatedly beaten and raped by the men who paid her for sex. Her first victim, Richard Mallory was a convicted sex offender.
Arrest, conviction and sentence: Arrested on January 9, 1991. Wuornos was arrested after her lover, Tyria Moore, told police about the murders and agreed to cooperate. Moore was not charged with any offenses. Wuornos later gave investigators a statement admitting to the murders but she said she killed in self-defense. During her trial for the murder of Richard Mallory, three psychologists testified for the defense that Wuornos suffered from borderline personality disorder, impairing her ability to conform her conduct to the requirements of the law. After about 90 minutes of deliberations, the jury returned a guilty verdict. At her sentencing hearing, Wuornos claimed that police coerced her into confessing. The judge sentenced her to death. She pleaded no contest to the other five slayings. She was executed on October 9, 2002, after voluntarily ending her appeals, saying that she would kill again if released.
Number of confirmed victims: At least 15
Years and location: 1970s-1990s, Washington state
Characteristics: A married father of five who flew helicopters in the Army and the National Guard, Yates predominantly preyed on prostitutes. One of the victims was buried in Yates' yard.
Arrest, conviction and sentence: Arrested on April 18, 2000. Yates was arrested after police matched fibers found on the body of a dead prostitute to Yates' car, which also had blood on the seatbelt and seat. DNA testing and other evidence linked Yates to at least 12 murders. He later pleaded guilty to 13 killings in exchange for a life sentence (408 years) in lieu of the death penalty. In 2002, he was convicted of two additional murders in a different county and sentenced to death. Yates' attorneys have repeatedly appealed the ruling but he remains on death row awaiting execution at the Washington State Penitentiary.
Number of victims: 29
Years and location: 1979-1981, Georgia
Characteristics: Over the course of 22 months, 29 African-American children and teens were murdered in the Atlanta area. The FBI worked with local authorities to investigate the killings, which detectives believed were linked.
Investigation: In 1981, the Reagan administration allocated more than $2 million in federal funds to help police track leads and provide funding for youth programs to keep kids safe after school. On June 21, 1981, a man named Wayne Williams was arrested and charged with the murders of two young men whose bodies were found in the Chattahoochee River. Although prosecutors said the two murders were connected to the child killings, Williams was never charged with the other crimes. He was convicted on two counts of murder and sentenced to two consecutive life terms in prison. He has maintained his innocence. In 2005, the DeKalb County Police reopened their investigation into five of the killings.
Number of victims: At least 11
Years and location: 1962-1964, Massachusetts
Characteristics: During the late spring and summer of 1962, six women between the ages of 55 and 85 were found dead in Boston and its suburbs. After a few months of quiet, younger victims began turning up. Mary Sullivan, 19, was the final victim, murdered in January of 1964. Albert DeSalvo, an inmate at a psychiatric hospital, confessed in 1965 that he was the Boston Strangler.
Investigation: Although DeSalvo claimed that he killed the women, police lacked physical evidence tying him to the murder scenes. He was instead tried for a series of robberies and sexual assaults. DeSalvo was convicted on all counts and sentenced to life behind bars in 1967. Six years later, he was stabbed to death in prison. In 2013, investigators found DNA connecting DeSalvo to Sullivan's murder. The DNA at the crime scene matched DNA collected from DeSalvo's exhumed corpse. Investigators tried to locate DNA from the other murders but have not yet been able to find additional biological evidence.
Number of victims: At least 5
Years and location: 1960s, California
Characteristics: During a string of seemingly random killings, phone calls and letters were received by police and newspapers from a person claiming to be the murderer. The letters were laden with mysterious symbols and references to astrology. Zodiac claimed that he or she killed as many as 37 people. After the last known murder in 1969, Zodiac mailed a piece of the victim's shirt, along with a letter to the San Francisco Chronicle.
Investigation: In 2002, a San Francisco homicide detective said more than 2,500 people had been considered suspects in the case. In 2018, police sent two of Zodiac's letters to a lab, hoping to find DNA on the stamps or the envelope flaps.