Famous Serial Killers Who Committed History's Worst Crimes

Torture rooms —including one that expelled poisonous gas — filled the Castle to the brim. Holmes would invite people into these rooms and then kill them in a variety of horrific ways.

Holmes eventually left Chicago for Texas, where he planned to open a similar death hotel. These plans quickly fell through, though, and so he wandered across the U.S. and Canada. Police originally arrested him in Missouri on charges of selling mortgaged goods but after some investigation found out the true depth of his crimes.

Police were able to confirm nine murders but believed that Holmes may have killed up to 200 people over the course of his life, a number they based on missing people reports during the time of his criminal activity. U.S. authorities hanged Holmes in 1896 at Moyamensing Prison.

The cops finally arrested Nelson in June 1927 in Canada, where he had murdered his last two victims. The husband of Emily Patterson, one of his last victims, found his wife's body under their bed. This prompted the investigation that soon led to Nelson's arrest. Canadian authorities quickly sentenced him to death and hanged him the following January.

In 2006, Alexander murdered his final victim, Marina Moskalyova. On watching subway footage, police identified Pichushkin as Moskalyova's escort and used this as evidence that would lead to his arrest and final conviction. Pichushkin is now serving life in prison.

It was only when 15-year-old Robert Jerome Piest went missing that the police began to suspect Gacy, as he had seen the boy just before his disappearance. Authorities began interviewing people in connection with Gacy and ultimately searched his home, where they found the remains of his victims. Once the police had arrested him, Gacy reportedly said, “The only thing they can get me for is running a funeral parlor without a license.”

After sitting on death row for 14 years, he was finally executed by lethal injection in 1994.

What happened next was a lot more grim: Haigh would dispose of the bodies by soaking them in acid, which disintegrated them.

Haigh's murder of Olive Durand-Deacon would signal the end of the "Acid Killer's" run. Durand-Deacon's friend reported her missing shortly after the murder, and the police began to investigate Haigh. While searching his workshop, they found human gallstones and a small part of some dentures. Authorities arrested Haigh, and soon he went on trial for murder.

In an apparent attempt to avoid the death penalty, Haigh decided to plead insanity, claiming that he also drank the blood of his victims.

The insanity plea didn't work, and the judge sentenced Haigh to death. On August 19, 1949, authorities hanged him at Wandsworth Prison.

Ramirez's prior criminal record for lesser crimes would ultimately do him in. One witness identified an orange Toyota that Ramirez drove while fleeing a crime scene, and the license plate number led police to his file, which prompted a manhunt. Suddenly, his face appeared on the front page of every newspaper in the area. Ramirez attempted to flee, but a group of locals apprehended him, holding him captive until police arrived.

A judge called his crimes acts of "cruelty, callousness, and viciousness beyond any human understanding" and sentenced Ramirez to 13 death penalties. Ramirez would not see a single one: the serial killer died while waiting on death row in 2013.

In the end, however, police definitively attributed just one murder to Toole, that of six-year-old Adam Walsh, whom he admitted to decapitating. In 1996, Toole died in prison of cirrhosis.

Officers first caught Bundy in 1975 in Florida, but he somehow managed to escape and commit more crimes over the following three years. In 1978, the police captured Bundy for the second time and a court sentenced him to three death penalties. He died in the electric chair in 1989.

Gary Ridgway, known as the Green River killer, carried out the killings in Seattle, and though he has confessed to a great number of them, it's not clear how many he actually killed. Today, he's still alive and serving a life sentence in Florence, Colorado.

During the 1920s and 1930s, police believed Fish had killed up to nine people in New York, although he only confessed to three. In 1928, Fish slipped up after killing ten-year-old Grace Budd. He'd abducted the girl, telling his parents that he was taking her to a party. He later sent the girl's mother an anonymous letter in which he claimed to have strangled and then eaten the child.

The paper on which Fish wrote the letter led the police to him. In 1935, a judge sentenced him to death by electric chair.

Between 1585 and 1609, accounts allege that she enlisted the help of four accomplices to torture and kill young women and children for her pleasure. Rumors of her crimes started to sweep through high society, and it was her guardian György Thurzó who finally arrested Bathory after reportedly finding one dead girl and another dying on the grounds.

Since her family was so very well-to-do, Bathory never had to face a trial, but she was imprisoned in 1609. She died of natural causes five years later.

Police caught him in 1964, and DeSalvo confessed to killing 13 women. Shortly after the authorities transferred him to a high-security prison, they found him stabbed to death in 1973. No one was ever convicted of his murder.

"You can cry and stuff, like the rest of them, but it won't do any good. We are pretty -- ha, ha -- cold-hearted, so to speak," says Ng in one of the two videotapes showing the torture and murder of their victims.

However, it wasn't Ng's killings that led police to him, but his shoplifting. In 1985, Ng tried to steal a vice from a San Francisco store. The store owner called the cops after Ng had left, and when Lake returned to supposedly pay off the debt, the police were suspicious of him since he did not match his ID. In fact, the man on the identity card was Robin Stapley, who was missing at the time. This prompted the police to search the cabin, where they found evidence of the murders, including records and tapes.

Ng fled to Canada, where police there arrested him for yet another theft incident. They then sent him back to California, where authorities tried him for murder. The 55 year old is currently awaiting the death penalty.

Despite the gravity of his crimes, he received just a 22-year sentence, as Colombian law only allowed up to a 30-year sentence for any crime. Likewise, since Garavito helped the police find some of his victims' bodies, his overall sentence was reduced. Garavito is currently in prison, carrying out that sentence.

Two undercover police officers finally apprehended Haarmann when he was arguing at a train station with teenager Karl Fromm, whom Haarmann had previously raped. Soon after, Fromm told the police of this crime, and they began to search Haarmann's home, where they found evidence of his many murders.

Even among other infamous serial killings, these murders were particularly gruesome: Haarmann would often mutilate and dismember his victims, sometimes biting right through their necks. He was beheaded at Hanover prison in 1925.

The authorities already knew of Bonin because they had previously convicted him of sexual assault and the murder of a young hitchhiker in 1979. While on parole, he went on to molest another young boy, an act which should have landed him back in prison but didn't due to a "clerical error."

Police then began to surveil Bonin in 1980 and soon arrested him. He spent many years on death row and died via lethal injection in 1996.

At his trial, the killer narrowly escaped the death penalty (because Ukraine had just entered the Council of Europe, which prohibits its members from using the death penalty) and instead got life in prison. Nevertheless, he died of heart failure in 2013.

Corll attempted to kill both of his accomplices in 1973, but Henley shot Corll dead before he could carry out the act.

Either way, the cops caught Wuornos in 1991, after witnesses had seen her driving a victim's car and gave an accurate description of her. After a lengthy trial, the judge ordered the death penalty.

In 2001, Wuornos chose to terminate any pending appeals and came clean about her motives, writing: "I killed those men, robbed them as cold as ice. And I'd do it again, too. There's no chance in keeping me alive or anything, because I'd kill again. I have hate crawling through my system...I am so sick of hearing this 'she's crazy' stuff. I've been evaluated so many times. I'm competent, sane, and I'm trying to tell the truth. I'm one who seriously hates human life and would kill again."

On October 9, 2002, she was executed by lethal injection.

A Florida Highway Patrol trooper finally caught Knowles with a stolen car in late 1974. However, Knowles was able to escape and kill the trooper before a civilian with a shotgun happened to find him evading authorities nearby.

A month later, while in a vehicle with Sheriff Earl Lee and Agent Ronnie Angel, Knowles grabbed the sheriff's gun in an attempt to shoot his captors. During the struggle, Angel shot Knowles dead.

In 1984, he was taken into custody after being caught trying to lead a young girl away from a bus station. He was released, however, when the results of a blood analysis suggested his blood type didn't match the semen found at the scene of his crimes.

When he was caught several years — and many murders — later emerging from a forest with bloody hands, the police put him under surveillance and later arrested him. A test revealed his blood and semen type were different from each other. He was sentenced to death for each of his 52 murders and executed by gunshot to the head in 1994.

In 1924, when Denke's attack on a homeless man failed, the police were alerted. They searched Denke's home and found a horrifying collection of bones, including 120 toes, and a ledger recounting at least 30 murders. Denke hanged himself in his cell before the trial.

In 1977, Kearney broke his pattern of killing strangers and murdered an acquaintance. When police discovered Kearney had been seen with the dead teen, they tracked him down, and he pled guilty to 35 murders to avoid the death penalty. He is currently serving out a life sentence.

What they didn't know was that Eyler was responsible for the deaths of some 17 other young men — something they only found out when his lawyer released a list of his other victims after Eyler's death in prison in 1994. He had compiled the names in a failed attempt at a plea bargain.

In 1993, police were searching the area of a recent murder when they found an abandoned shack with a noose hanging from the ceiling in preparation for a new murder. A stakeout team caught Ryakhovsky, who confessed to the murders and was sentenced to death by firing squad.

But a 1996 moratorium on executions in Russia meant his sentence was commuted, and he died of tuberculosis while serving a life sentence in a penal colony.

Four years in prison only made things worse. Out again, he started raping and murdering old friends, acquaintances, and eventually strangers along the I-5 corridor. The police knew it was him, but the evidence was circumstantial — until finally a witness named him in a lineup. He was sentenced to life in prison, and the state of Oregon, hurting for cash, decided not to pursue his other crimes — he was already behind bars for life.

Police knew the crimes were connected, but they weren't looking at Gaidamachuk until one of her elderly victims escaped and told them the killer was a woman — a possibility they hadn't considered. A neighbor had seen Gaidamachuk leaving the battered woman's home, and they arrested her shortly thereafter.

In 2012, she was sentenced to just 20 years in prison for 17 murders. Her victims' families continue to campaign for a longer sentence.

Though he was a key suspect in the early days of the investigation, the lack of evidence eventually led the police to look elsewhere. They didn't catch him until he was pulled over for drunk driving one night — with a dead man in his passenger seat.

In 1989, Kraft was found guilty of sixteen counts of murder and sentenced to death. He is currently on death row in California.

Edwards fled the house in handcuffs and told police about the assault — and the strange-smelling 57-gallon drum in Dahmer's bedroom. The police found four severed heads in Dahmer's kitchen and arrested him. In 1992, Dahmer pleaded guilty to 16 murders.

He was bludgeoned to death by a fellow inmate in 1994. The inmate said God had told him to do it.

He was difficult to catch — the age of his victims meant that several deaths were attributed to natural causes. But when police searched his home, they found momentos from a staggering number of previously unidentified killings.

In 1991, he was sentenced to 440 years in prison, and in 2002, he was stabbed and killed by fellow inmates.

He had killed more than 17 times before an FBI profiler hit the mark: Special Agent Roy Hazelwood told police to look for an experienced hunter with poor self-esteem, a stutter, and a history of rejection. When police searched Hansen's property, they found jewelry belonging to his victims.

Hansen plead guilty to 17 murders and told investigators about 12 that were unknown to them, though a number of markings on the aviation map remain unexplained. In 2014, Hansen died while serving a life sentence in prison.

In the course of his conviction, he gave a DNA sample — a DNA sample that matched DNA recovered at the scene of two murders. In the end, they tied him to thirteen murders, for which he was sentenced to death. Turner now waits on death row, and his conviction has freed a man who was wrongfully accused of Turner's crimes.

He was finally caught for the murder of his 13th victim, a man who was simply weeding his suburban lawn when Mullin pulled over and shot him in broad daylight. Witnesses gave police Mullin's license plate number, and the authorities caught up to him minutes later.

Mullin confessed to all the murders and said the voices in his head made him do it. He was sentenced to life in prison.