30 Dumbest Mistakes That Got Killers Caught

30 Dumbest Mistakes That Got Killers Caught

Welcome to WatchMojo, and today we’re looking at the slip-ups made by killers that led to their downfall.

Sheer Arrogance

John Wayne Gacy

Thanks to this man, your childhood fear of clowns is totally valid. By day, John Wayne Gacy was the friendly contractor who also entertained kids as “Pogo the Clown.” But beneath that mask was a monster who murdered over 30 people. Gacy’s downfall eventually came from his own carelessness. He buried most of his victims in the crawl space beneath his home, probably thinking no one would suspect him. That changed when Robert Piest went missing, and suspicion turned to him. During the investigation, police found IDs and items belonging to other people—a devastating clue. Gacy even invited investigators into his home, where one detective caught the horrific stench of decay. That unmistakable odor exposed the “Killer Clown.”

Letting a Victim Go

Peter Kürten

From sexual assaults to arson and attempted murder, Peter Kürten’s crimes went unchecked for far too long. He terrorized people in 1929, although his history of brutal attacks stretched back even further. His downfall came when he assaulted Maria Budlick, who eventually led police to his doorstep. Initially, Budlick hadn’t intended to report the crime, but the letter describing her ordeal was opened at the post office. The clerk who read it alerted police, which prompted Budlick to come forward and expose Kürten’s address. Though Kürten initially escaped capture, he eventually confessed his crimes to his wife, knowing that his end was near. He was arrested after his wife revealed his location, and he freely admitted to his crimes.

Hiding Bodies in His Home

John Christie

No matter how long someone hides their evil, the truth always finds a way out. That was certainly true for John Christie, an English serial killer active in the 1940s and early 50s. Christie probably thought he’d never been caught. After murdering Beryl Evans, he even testified against her husband, Timothy Evans, who was wrongly accused of the crime. But Christie’s dark secrets couldn’t stay buried forever. After he moved out of 10 Rillington Place, new tenants made a chilling discovery—three female bodies hidden in a papered-over alcove in the kitchen. When police searched further, other remains were found, including his wife’s. Christie fled but couldn’t run for long. He was soon captured and hanged for his crimes.

Boasting About His Crimes

Richard Kuklinski

What is it with some criminals and that urge to brag about their crimes? We’ll never understand—but in Richard Kuklinski’s case, it helped bring him down. Known as the Iceman, Kuklinski came under police scrutiny after a series of gangland-style murders led investigators to him. When police launched a full-scale investigation in the mid-to-late 1980s, their real breakthrough came when an undercover agent Dominick Polifrone befriended Kuklinski. During their meetings, Kuklinski couldn’t resist boasting about his killings, even explaining in detail how he accomplished them. Using Polifrone, the police set up a fake hit on a fictitious target, then moved in for the arrest. Kuklinski thought he was untouchable—but his own arrogance and need to brag eventually sealed his fate.

Releasing a Manifesto

Ted Kaczynski (Unabomber)

Infamously known as the Unabomber, Ted Kaczynski went from a respected mathematics professor to one of America’s most chilling domestic terrorists. Despite all his intelligence, it was something as simple as his writing style that got him caught. Ted’s 35,000-word manifesto was filled with his usual phrasing, tone, and ideas he used to write letters to family members, especially his brother. When the FBI published the manifesto, hoping someone would recognize the author’s writing style, his brother David did. That marked the beginning of the end of Kaczynski’s reign as the Unabomber. David alerted the authorities about his suspicions and turned in the letters. Soon, Kaczynski was exposed as the mastermind behind the 1978 and 1995 mailbombing campaign.

Inviting a Third Party

Ian Brady & Myra Hindley

When the Moors Murderers—Ian Brady and Myra Hindley- killed Edward Evans in front of David Smith, they probably weren’t thinking straight. Inspired by sadistic fantasies, Brady had been able to draw Hindley into his world of murder and manipulation. Together, they lured and killed various young people and probably thought they could recruit Smith into this twisted world of theirs. But that was a huge miscalculation. After Smith, Hindley’s brother-in-law, witnessed the gruesome murder of Evans, he was shaken. He went home and told his wife everything he had witnessed, and the next morning, they alerted the police. That call exposed everything. When police searched the house, they found evidence linking Brady and Hindley to multiple murders.

A Pair of Glasses

Nathan Leopold & Richard Loeb

When you’re intelligent and wealthy like this murderous pair, you might think you can pull off the perfect crime—whatever that means. But sometimes, you just can’t be too smart. Nathan Leopold and Richard Loeb made some dumb mistakes that sealed their fates. After murdering Bobby Franks, they hid the body poorly, and it was soon discovered. Their next blunder? Leaving a pair of glasses that traced straight back to Leopold. Still, they could’ve gotten away with murder if not for yet another damning clue. They had sent a ransom note to their victim’s father, and that handwriting matched that of Leopold’s. For all their brilliance and planning, it was their own carelessness that exposed them.

Using His Own Typewriter

Harold Shipman

For over two decades, Harold Shipman secretly murdered his patients—mostly elderly women—and often pocketed their money. His undoing began in 1998, when the daughter of one victim, Kathleen Grundy, grew suspicious. After Grundy died, that same day her solicitors received a will stating she’d left her entire estate to Shipman, not her children. That immediately raised flags, prompting Grundy’s daughter to go to the police. When her mother’s body was exhumed, it showed lethal traces of heroin, something Shipman falsely claimed Grundy took voluntarily. His biggest mistake? Typing the forged will on his own typewriter and even leaving traces of his fingerprints. That discovery unravelled Shipman’s horrifying pattern of murders and ended the career of one of Britain’s most prolific serial killers.

His Compulsive Desires

Arthur Shawcross

A deeply disturbed killer, Arthur Shawcross’s perverse behavior at a crime scene ultimately led to his capture. Known as the Genesee River Killer, Shawcross terrorized New York in the late 1980s, targeting mostly sex workers. Shockingly, he’d even served time for murdering younger victims but was released—only to kill again. Shawcross’s downfall came in 1990 when police helicopters spotted him standing close to a van near one of his victims’ bodies by the Genesee River. He seemed to be reliving the pleasure of the attack. Investigators on the ground chased after his vehicle and arrested him shortly after. Once in custody, Shawcross confessed to more than ten murders. This just goes to show that even cunning criminals can expose themselves through compulsive desires.

A Detailed Notebook

Henri Landru

While World War I left many grieving and desperate, Henri Landru saw it as a perfect cover for murder. Disguising himself as a charming suitor, he lured widowed and single women to their deaths, then burned their bodies to erase all trace. Thanks to one particularly determined victim’s sister, who kept pressing the police, he was eventually exposed. Investigators later discovered that Landru always bought a return ticket for himself to his villa in Gambais—but only bought one-way tickets for the women he lured there. He never intended for them to return. Another crucial piece of evidence was his notebook— a small ledger detailing his victims and other important information. Though the women’s bodies weren’t found, Landru’s notebook helped to seal his fate.

Debit Card Carelessness

Israel Keyes

This otherwise meticulous serial killer was undone by a lapse in his otherwise calculated methods. In 2012, after abducting and murdering Anchorage barista Samantha Koenig, Keyes used her debit card to withdraw ransom money across several states – transactions which allowed law enforcement to track his movements. On March 13, 2012, Texas Highway Patrol officers arrested Keyes in Lufkin, Texas, after noticing his vehicle matched one identified in surveillance footage. A search revealed Koenig's ATM card, cell phone, and dyed cash from a bank robbery, sealing his fate. Despite Keyes’ efforts to remain anonymous, a digital breadcrumb trail led to his capture.

Capturing a Young Forensic Genius

Bobby Joe Long

In November 1984, Bobby Joe Long abducted Lisa McVey in Tampa, Florida. During her 26-hour captivity, McVey manipulated Long into trusting her, strategically left fingerprints in key areas, and memorized critical details about his appearance, vehicle, and residence. After her release, she provided this information to the police. Forensic evidence, including matching red carpet fibers, linked Long to multiple crime scenes. He confessed to the murders of 10 women and was sentenced to death. McVey’s bravery and quick thinking were instrumental in ending Long's killing spree, and she’d go on to become a police officer.

DUI

Randy Kraft

Known as the "Scorecard Killer" and “Freeway Killer,” Kraft was apprehended in 1983 during a routine traffic stop in Orange County, California, when a Highway Patrol officer noticed him driving erratically and pulled him over. Sure enough, the officers discovered open beer bottles in the vehicle – but that’s not all. There was also a deceased Marine in the passenger seat, as well as tranquilizers and a list of coded references to victims. This list, later dubbed the "scorecard," contained cryptic entries believed to correspond to Kraft's victims. The evidence led to Kraft's conviction for 16 murders, though he is suspected of committing up to 67.

Dropping Something Important

Peter Goebbels

It doesn’t get much more incriminating than leaving your ID at the crime scene. Between 1984 and 1985, Goebbels strangled four women in Germany, saving his crimes for Saturdays and Sundays to accommodate his day job at a factory. While police initially struggled to nab the culprit, Goebbels offered himself up on a platter – albeit accidentally – when he dropped his identification card as he fled from police. Goebbels isn’t one of the better known serial killers, but he’s certainly noteworthy for the way he was caught.

Novel

Krystian Bala

They say “write what you know,” but that advice backfired spectacularly for Bala. In 2007, the Polish author was convicted of orchestrating the 2000 torture and murder of Dariusz Janiszewski, a businessman suspected of having an affair with Bala’s ex-wife. The case went cold until 2003, when Bala published “Amok,” a novel featuring a murder eerily similar to Janiszewski’s – down to details that had never been made public. Investigators also discovered that Bala had sold the victim’s cell phone online just days after the killing. Though the evidence was circumstantial, it was compelling enough to secure a 25-year prison sentence. Bala’s attempt to blur fiction and reality ultimately exposed him as a killer hiding in plain sight.

Shirt

Timothy McVeigh

You’ve no doubt heard of the Oklahoma City bombing, a devastating domestic terrorist attack in 1995. The perpetrator, Timothy McVeigh, detonated a truck bomb outside the Alfred P. Murrah Federal Building in the state’s capital, killing 168 people and injuring over 600 more. Just 90 minutes later, State Trooper Charlie Hanger pulled over McVeigh for driving without a license plate. During the stop, Hanger also discovered that McVeigh was illegally carrying a concealed weapon – not to mention wearing a shirt bearing the same phrase reportedly uttered by Abraham Lincoln’s killer. It was this traffic stop that led to McVeigh's identification and conviction.

Arrest by Chance

Peter Sutcliffe

You’d be surprised how many serial killers are done in by license plates. Such was the case of Sutcliffe, or the Yorkshire Ripper, who had previously evaded capture for years despite multiple run-ins with law enforcement. On January 2, 1981, Sutcliffe’s luck ran out when officers in Sheffield stopped him for driving a car with false plates. During the arrest, Sutcliffe requested to relieve himself and used the opportunity to hide a knife and hammer near the scene. A subsequent search uncovered these weapons, and when confronted with the evidence, Sutcliffe confessed to murdering 13 women and attempting to kill seven others between 1975 and 1980.

Big Mouth

Robert Durst

This famed real estate heir had long been suspected in multiple disappearances and murders, including that of his wife Kathleen McCormack. But it was the 2015 HBO documentary series “The Jinx” that brought new evidence to light. In the series' final episode, Durst was caught on a hot mic in the bathroom, muttering about what he’d done. This apparent confession, along with a letter linking him to the 2000 murder of his friend Susan Berman, led to his arrest on March 14, 2015, just one day before the finale aired. Durst was convicted of Berman's murder in 2021 and sentenced to life in prison, where he died a year later.

Plumbing Problem

Dennis Nilsen

In 1983, this Scotsman’s murderous spree came to an end thanks to a plumbing problem. Neighbors in his North London apartment complex complained about clogged drains, prompting a plumber to investigate. To the plumber’s horror, human flesh and bones were blocking the pipes. Nilsen, a former civil servant, had been luring young men to his flat, where he killed and dismembered them, disposing of remains by flushing them down the toilet or hiding them under floorboards. Upon arrest, Nilsen confessed to murdering at least 15 men between 1978 and 1983. He was convicted of six counts of murder and two of attempted murder, receiving a life sentence.

Bad Hair Day

Earle Nelson

Active in the 1920s, Nelson was sometimes called the “Gorilla Killer” – not because his victims were apes, but because he sported a stocky build with long arms and sizable hands. Nelson’s modus operandi involved renting rooms from landladies, whom he would then strangle. His comeuppance came when he visited a barbershop in 1927; the man cutting his hair noticed dried blood and scratch marks on Nelson’s scalp, and was understandably unsettled. Only a few days later, police nabbed the “Gorilla Man” in Killarney, Manitoba. In January of the next year, he was executed by hanging in Winnipeg.

Neville Heath's Hotel Stay

This Brit’s killing spree was cut short by one careless check-in. In 1946, Heath, a WWII veteran, developed a strange pattern of checking into hotels and picking up women – two of whom he murdered. And he might have gotten away with it, but for the critical mistake of using his real name when checking in with one of his conquests at a hotel. Though he other times was careful enough to use pseudonyms, Heath apparently believed that simply adding the military title "Lieutenant-Colonel" to his name would be enough to avoid suspicion. This misguided decision not only led directly to his arrest but also secured his place among the most incompetent criminals of all time.

Joel Rifkin's Missing License Plate

This Long Island native is currently serving a 203-year sentence for the brutal deaths of at least nine women, though he actually confessed to several more. Rifkin targeted vulnerable females in the New York City area, typically dismembering them and scattering their remains in rivers, woodlands, and golf courses. In June 1993, he was brought to justice during a routine traffic stop because he was driving without a license plate. When he attempted to flee, a high-speed chase ensued, ending with a collision. Upon inspecting his truck, officers discovered the decomposing body of Tiffany Bresciani. The moral of Rifkin’s story? Never drive without a license plate. Or run from the police. Or, you know, murder people.

Maury Travis' Map

When you’re this vocal about your crimes, should it really come as a shock when you end up in prison? This St. Louis waiter didn’t seem to think so. In the early 2000s, Travis left a trail of victims and even created a torture chamber in his basement, where he filmed grisly snuff films. When a story about one of the slayings was published in the newspaper, Travis responded with what he thought was an anonymous letter, attaching a printed map that revealed the location of the body. What Travis failed to realize was that the map contained a URL identifier, which gave investigators the evidence they needed to apprehend Travis. Between this and the lovely videos, Travis had a lot of explaining to do.

David Berkowitz's Parking Ticket

Better known as the “Son of Sam,” Berkowitz tormented New York City in the 1970s with a series of random shootings. Claiming to be in cahoots with a demonic dog, he taunted the police and media with handwritten letters that fueled public fear. One night, Berkowitz parked near a fire hydrant in Brooklyn, which any experienced driver knows is a parking no-no. A witness later reported a suspicious figure near the scene, and police began combing through traffic tickets issued in the area that night. Upon further investigation, they found a rifle and a bag filled with ammunition in Berkowitz’s vehicle, leading to his swift arrest and an alarmingly proud confession.

Charles Ng's Stolen Fish

Imagine nearly getting away with multiple gruesome murders…and then sacrificing it all for a can of salmon. With his accomplice Leonard Lake, Ng subjected people of various ages to horrific abuse before taking their lives. They had even created a horrendous dungeon on a property they used in Calaveras County, California. While on the lam in Canada, Ng – who suffers from kleptomania – shoplifted some canned fish from a department store. His arrest for this offense eventually revealed him to be wanted in the United States. That small theft set off a chain of events that ended his deadly spree and landed Ng on death row.

Albert Fish's Watermark

Known as the “Werewolf of Wysteria,” the “Boogey Man,” and the “Gray Man,” Fish was infamous for his carnage. However, his reign of terror over New York City came to an end with a careless mistake involving a single piece of paper. After kidnapping and cannibalizing young Grace Budd in 1928, he sent a gruesome letter to her family, filled with chilling details of the crime and erratic psychological ramblings. Unbeknownst to Fish, the envelope containing the letter bore a distinctive watermark reading “New York Private Chauffeur’s Benevolent Association.” This small clue led the police directly to the rooming house where he was staying, resulting in his arrest.

The Lainz Angels' Arrogance

The so-called “Lainz Angels of Death” consisted of four Austrian nurse’s aides who preyed upon the feeble and elderly. The women would forcibly cause patients to overdose on morphine and tranquilizers; other times, they drowned patients by filling their lungs with water. Although the Angels claimed they simply wanted to put infirm people out of their misery, it’s largely believed they acted out of sadism rather than mercy. To add another layer of “disturbing” to this story, the Angels would likely have gotten away with countless more murders, had they not been overheard arrogantly discussing their secret out loud at a tavern.

Charles Schmid's "Show and Tell"

Time for a Serial Killer Pro Tip: After you’ve killed someone, it’s generally not a great idea to show off the body. Schmid – also known as the “Pied Piper of Tucson” – strangled his girlfriend Gretchen Fritz, as well as her younger sister Wendy, in 1965. This was more than a year after he had bludgeoned another young woman named Alleen Rowe to death with a rock. Apparently unable to resist bragging about his exploits, Schmid showed his best friend, Richard Bruns, where he had buried the sisters’ bodies. Bruns became frightened and alerted the authorities, bringing Schmid’s spree to a close.

Ted Bundy's Stolen Car

Bundy is often considered one of the slickest and most cunning serial killers in history – but this story doesn’t exactly support that idea. You’re likely familiar with Bundy’s dark deeds; he used his good looks and charisma to gain the trust of dozens of women, whom he then proceeded to murder in cold blood. This proud, pompous psychopath managed to escape police custody several times before finally being caught in Florida, where he was driving a stolen vehicle - which eventually turned out to have evidence of his misdeeds. Though he attempted to flee once more, this encounter resulted in his capture and, ultimately, execution.

Dennis Rader's Floppy Disk

The infamous "BTK Killer" eluded capture for three decades until a foolish lapse of judgment cost him his freedom. Beginning in the 1970s, Rader terrorized the Midwest with the vicious and mysterious slaying of numerous citizens. Like many of his kind, he enjoyed taunting detectives with letters and clues. In 2004, after years of silence, Rader asked in one of his notes whether he could safely send a floppy disk without being traced. The police, playing along, assured him it was fine, and he naively believed them. This, of course, proved to be the rookie mistake that finally did Rader in. Police used information on the disk to gain his identity.

Who is the most chilling of these serial killers? Let us know in the comments.