10 Most Terrifying and Disturbing Serial Killers

10 Most Terrifying and Disturbing Serial Killers
VOICE OVER: Peter DeGiglio WRITTEN BY: Jordy McKen
Prepare to get seriously creeped out. For this list, we'll be looking at the most notorious serial killers whose terrifying stories will keep you up late at night! Our countdown includes John Wayne Gacy, David Parker Ray, Albert Fish, and more.

10 Most Terrifying and Disturbing Serial Killers

Welcome to WatchMojo, and today we’re counting down our picks for the 10 Most Terrifying and Disturbing Serial Killers.

For this list, we’ll be looking at the most notorious serial killers whose terrifying stories will keep you up late at night!

Who’s the scariest serial killer you know of? Comment their name down below!

#10: Robert Hansen

As a teenager, Robert Hansen would take part in hunting to escape his rough home life. But, as he got older, his victims went from animals to human beings. He would abduct women, often sex workers, and assault them before driving or flying them out to the wilderness. Here was where he would hunt them down like prey, toying with their lives. Nicknamed the “Butcher Baker” by the media, Hansen was confirmed to have assaulted and killed at least 17 women. In 1983, a teenage sex worker named Cindy Paulson was set to be on that list. However, she managed to escape when he was stocking his plane and alerted the authorities who would arrest him. He received a sentence of 461 years and died in prison after serving 31 years.

#9: Israel Keyes

What’s most terrifying for the police and the public is a killer with no M.O. But, to make things worse, how about one who was also trained by the U.S Army? This was the case of Israel Keyes. Across the country, Keyes had set up “kill kits,” which gave him access to equipment wherever he decided to attack someone. After he killed 18-year-old Samantha Koenig, the FBI was able to track his bank account use and make an arrest following the demand for a ransom. Once he was in custody, however, it was discovered that Keyes was responsible for the murder of multiple victims. Before he faced trial in 2012, Keyes took his own life, and taking with him information that might have been used to solve other cases.

#8: John Wayne Gacy

One pretty common phobia is clowns. And the case of John Wayne Gacy certainly didn’t help ease any of those fears. Gacy regularly performed in a clown persona at parties and events; but, behind the scenes, he was a rampant killer of boys and men. In 1978, after suspecting the police were on to him, a paranoid Gacy would confess his crimes to his lawyers. The police had what they needed to search his house, where they would find several remains in his crawl space. He was charged with the assassination of 33 young men and would spend 14 years on death row before being executed by lethal injection.

#7: Marcel Petiot

With France under German occupation in the 1940s, Marcel Petiot, a doctor, preyed on those attempting to escape persecution. Later claiming he was working for the resistance, even though there was no evidence, Petiot set up a fake escape route under the name “Dr. Eugène.” He gave those running a fake vaccine that contained cyanide before stealing their valuables and disposing of their bodies. With 23 remains discovered, Petiot was executed in 1946. Meanwhile, over in Germany a few decades earlier, a man by the name of Karl Denke set his sights on travelers and the homeless. Despite being a beloved member of his community, it was discovered he was responsible for slaying, consuming, and reportedly selling his victims to unsuspecting customers.

#6: Jeffrey Dahmer

From his late teens, Jeffrey Dahmer began a horrific killing spree. His victims were all men or boys, and many of his later crimes involved unspeakable acts to the bodies. In 1991, Dahmer enticed Tracy Edwards back to his apartment with the promise of beer and payment for photographs. However, Edwards realized something was wrong and managed to escape. After he flagged down police officers, Dahmer’s apartment was investigated and grim evidence was found, leading to Dahmer’s arrest. He was convicted of 15 murders and sentenced to life imprisonment. However, in 1994, he was fatally attacked by fellow inmate Christopher Scarver.

#5: David Parker Ray

Sometimes, killers go that extra, terrifying mile with their modus operandi. David Parker Ray modified a trailer that would be labeled his “toy box.” The trailer was soundproofed and filled with instruments for his violence. He would abduct women, abuse them for months in the trailer, and presumably eventually end their lives, sometimes with accomplices, one of them being his girlfriend, Cynthia Hendy. In 1999, a woman managed to escape the "toy box" after three days and get help from a neighbor. The police immediately arrested Ray and Hendy. On a plea deal, Ray was sentenced to 224 years in jail, while Hendy, who testified against her former partner, got 36 years. It’s unknown how many women Ray killed, but some estimates are upwards of 60.

#4: Fred & Rosemary West

Occasionally, serial killers come in pairs. While Fred had murdered in the past before meeting Rosemary Letts, Rose’s first victim was, purportedly, Fred’s stepdaughter. The two then went on a rampage, assaulting and killing 9 other people together, including West’s first wife Catherine Costello and their daughter Heather West. Many of the bodies were buried on their properties. After investigating assault charges against the couple, the police found evidence of the violence. Although officially charged with 12 killings altogether, that number is estimated to be higher. In 1995, before his trial, West took his own life and Letts was sentenced to life in prison.

#3: Albert Fish

Nearly 100 years ago, New York had a killer on the loose nicknamed many things including “The Gray Man” and even “The Boogey Man.” (Honestly, it’s not too far off.) Albert Fish was a disturbed individual who targeted children. While we can’t exactly list off his crimes toward them, just know they’re terrible. To make things even more disturbing, the unhinged Fish sent the mother of one of his victims a letter describing what he did. Ten years after Fish began his acts, he was captured in 1934 after witnesses claimed to have seen with the missing children. Fish would admit to the murders, but would also claim he had over 100 victims. At his trial the following year, he was sentenced to execution, which was carried out in 1936.

#2: Harold Shipman

Doctors are meant to be people we all trust. This makes the case of Harold Shipman especially chilling. He was general practitioner in England who took people under his care only to end their lives. In 1998, one of his patients suddenly passed away, and a will – one that the family knew nothing about – gifted a lot of cash to Shipman. Police investigated the doctor and found evidence of forgery. Upon further examination, they found that many of his patients seemed to pass from overdoses of diamorphine. In 1999, Shipman was charged with the murder of 15 patients, many of whom were older women. He was sentenced to life in prison and, in the aftermath, there were thought to be as many as 250 victims.

#1: Pedro López

What’s worse than a serial killer? Well, how about a known one authorities can’t currently locate? Born in Columbia, Pedro López was a serial murderer across South America and was nicknamed “The Monster of the Andes.” In 1980, after attempting to abduct someone, López was arrested in Ecuador. He was soon charged with 110 homicides; however, López reportedly confessed that his victims could total more than 300. In 2006, the Guinness World Records actually named him the “most prolific serial killer” before it was taken down in bad taste. Unfortunately, López was released for “good behavior” in 1998 and was declared sane. But, as of 2002, after being linked to another murder, his whereabouts are unknown.