11 Warning Signs Everyone Ignored About These Serial Killers

Imagine finding out someone you knew was a serial killer. In an instant, every interaction they'd ever had with you or anyone else would change dramatically in your mind. Seemingly innocuous quirks in their personalities, weird stories from their early days, and strange behavior can all be written off in the short term, but the moment those events are known to involve a killer, they carry new meanings. We tend to give people a pass on questionable behavior, but that can come back to bite us when the truth comes to light. Any one of us could face the lens of an unforgiving TV camera as a true crime interviewer asks us how we missed all those obvious red flags.

Many of the telltale signs we associate with budding killers are present in countless people who clean up their acts as they age. Researchers have repeatedly linked childhood abuse with types of serial murder, but the overwhelming majority of abuse victims don't grow up to commit homicide. Early signs like a fascination with starting fires or a fondness for voyeurism are present in tons of teens who never kill anyone. Assuming someone will eventually become a serial killer is rarely a helpful stage in childhood development, so people often allow certain red flags to slip by unnoticed. However, there are other warning signs can't be so easily explained away. 

The following article includes descriptions of animal cruelty and child abuse.

Pyromania, or a general fascination with fire, is one of the most-cited telltale signs of a potential killer. Several known killers contribute to that understanding, but David Berkowitz might be the most prolific example. Berkowitz became known as "the .44-Caliber Killer" after he started his killing spree in 1976. His first victims were a pair of teenage girls, one of whom survived the encounter, but he quickly moved on to two couples, another pair of teenage girls, and a college student. Berkowitz killed six, all told, often leaving letters by the crime scenes and doing little to evade the law. Cops caught him after he received a parking ticket near a shooting, leading to six 25-year-to-life sentences. 

During his trial, Berkowitz spoke to a psychiatrist for the defense, sharing a couple of stories about his youth. David Berkowitz's chilling motivation made him something of a media darling. Berkowitz explained that he set so many fires in his youth that his fellow teens called him "Pyro." This evidently went completely unnoticed by authority figures, but it does provide another link between arson and murder. Berkowitz never lost his fondness for flames, as he maintained a diary that linked him to as many as 2,000 arsons in the Bronx. He temporarily served as a volunteer firefighter, despite apparently preferring to start dangerous blazes instead of putting them out. 

Jeffrey Dahmer is one of the most publicized killers in the history of true crime media. During his trial, TV coverage came from a variety of sources, bringing local and national attention to the case. Court TV famously aired the footage on a delay, allowing 20 seconds for network employees to quickly censor any of the extremely unpleasant details before they reached the audience. It was one of the most-watched court cases in TV history, and airing the footage across the nation triggered a flood of new information about Dahmer. One of the most notable emerging stories came from a group of people who grew up around Dahmer but kept the details to themselves.

After Dahmer's arrest in Milwaukee, some of his former neighbors spoke to the police in Dahmer's native Ohio. They recalled stumbling onto Dahmer's territory and finding a dog's severed head impaled upon a spike. Other neighbors reported seeing cats and frogs that had suffered a similar fate, pinned to trees and structures near Dahmer's home. Dahmer's neighbors kept this information to themselves for decades, ignoring the possible connections between torturing animals in youth and killing humans in adulthood. They ignored Jeffrey Dahmer's warning signs until it was far too late, only telling the world after he was arrested and in custody.

Jeffrey Dahmer had a difficult childhood that prompted him to turn to alcohol early as a coping mechanism. He started drinking at 13 and became notorious for his alcoholism the following year, eventually developing a reputation for drunken pranks. That isn't as absurd as it sounds, as 2015 statistics suggest that the average American is 13 or 14 years old when they have their first drink. Dahmer wasn't just getting hammered at high school parties, however. He began drinking scotch practically every school day by the time he was 16, earning the pity of his classmates for his public addiction.

Dahmer's drinking problem started early and stayed relatively consistent. He allegedly dropped out of higher education as a result of his addiction, pushing him to enlist in the U.S. Army. He wound up in Germany, where he reportedly drank to excess. His drinking problem eventually earned him an honorable discharge, sending him to Milwaukee to start his career as a killer in earnest. (He had murdered a hitchhiker at the age of 18, while still living in his parents' home.) Dahmer was arrested at least twice on alcohol-related charges, including one drunk and disorderly and one open container. Dahmer's alcoholism didn't get him into any further legal trouble, but it was an integral part of his early development that failed to raise red flags. 

Ted Bundy wasn't exactly a prankster in his early days, but he did have a need to control and harm others. He allegedly took great pleasure in causing harm to other youths in his hometown, even going so far to set up war crime-adjacent traps in his neighborhood.

Bundy's childhood friend Sandi Holt spoke to Netflix for their "Conversations With a Killer: The Ted Bundy Tapes" documentary and shed some light on the killer's early life. Holt alleged that Bundy built "tiger traps," which she described as pits full of spikes and hidden by vegetation (via USA Today). This matches the description of the punji spike trap that became iconic in the Vietnam War. She went on to recount an occasion in which a young girl fell prey to the trap, injuring her leg. Bundy apparently never suffered any known consequences for setting up a wartime spike trap, allowing him to graduate to more lethal methods.

Edmund Kemper had a lot of red flags in his childhood, but he also started killing pretty early. Born in California, Kemper moved to Montana with his mom and two sisters after his parent's divorce. His mother, a heavy drinker, frequently abused and berated her son while also showing concern for Kemper's odd behavior. Kemper slept in the house's basement, distancing him from his siblings and furthering his grudge against his mom, but Mrs. Kemper allegedly saw a safety concern in allowing him to share space with his sisters. He didn't help his case when, at 10 years old, he started cutting the heads off of his sisters' dolls.

The same year, Kemper would take his first life when he killed the family cat. He allegedly buried the poor animal alive, dug it up after it died, and cut off its head with a knife. Kemper reportedly killed another cat three years later, displaying its severed head on a platter. Even at that tender age, the young man demonstrated an obsession with removing heads. These red flags were not addressed until he left Montana at 15, returned to his father, and wound up living at his grandparents' house. Kemper killed his grandparents and spent five years in a mental hospital, but none of that prevented him from becoming a serial killer in later life. 

Any hardcore true crime fan knows that a lot of the genre only exists because cops don't always make good choices. Jeffrey Dahmer became the subject of one of the most egregious police mistakes in American history in 1991 when a 14-year-old Laotian boy named Konerak Sinthasomphone escaped Dahmer's Milwaukee home. Sinthasomphone was nude, visibly inebriated, and bleeding when a pair of young women found him. Those ladies phoned the police while fending off Dahmer, who insisted that the boy was his drunken lover and that there was no need to involve authorities. When the cops did arrive, they walked Dahmer and Sinthasomphone back to Dahmer's apartment and left without incident. 

The Milwaukee police officers completely ignored the endless red flags in the situation and left a boy in Dahmer's care. Dahmer immediately strangled Sinthasomphone to death, later claiming that he had another dead body just a few feet from the cops as they left Dahmer to his business. Protests broke out as Milwaukee citizens claimed that the officers were guilty of racism and homophobia. Those biases may have blinded the officers, pushing them to leave a defenseless boy to his grisly fate. Many maintained that the white officers listened to Dahmer, a white man, and ignored the state of the Laotian victim and Black witnesses. The officers were suspended, but they continued to defend their decisions. 

Richard Ramirez's early life included several well-known defining moments. At 5, he fell off of a swingset and suffered a head injury that resulted in several epileptic seizures. Many researchers have linked head injuries with serial murder, but it's no telltale sign on its own. A much more concerning incident emerged when Ramirez was 12, when his cousin, a Vietnam War veteran, showed him photos of brutally dismembered Vietnamese women. Ramirez allegedly became aroused by the nightmarish images, forever linking sex and death in his mind and creating some of the early signs of his future behaviors.

Ramirez later witnessed the same cousin shoot his wife, preceding Ramirez's first kill by several years. He was 24 when he committed his first known homicide, killing a 79-year-old widow. He went on to kill at least 13 people, almost always in home break-ins. Ramirez sexually assaulted many victims and left satanic symbols all over the scenes of various crimes. His public nickname became "The Night Stalker." Cops caught him by identifying a fingerprint at the scene of the crime, allowing them to broadcast his name and face to the world and eventually resulting in a successful arrest. He may have been easier to catch if anyone had kept track of the obvious red flags he exhibited as a young man.

Albert Fish is a great example of how easily red flags could pass without a trace in the 19th and early 20th centuries. Fish had a lot of mental illness in his family, but he didn't experience much of it in his earliest years. His parents put him up for adoption, leaving him in an orphanage where the young charges were routinely abused. Fish developed a fascination with suffering, experiencing pleasure from both watching and receiving violent punishment. He would take those interests with him when he left the orphanage and moved to New York with his mother. A decade later, he took to luring children from their homes and torturing them with various implements, including a nail-filled paddle. 

Self-harm was always a part of Fish's fascination with violence. He later married and had six children, all of whom became witnesses and participants in his sadomasochism. Fish's own children sometimes struck him with his nailed paddle at his request. He also frequently stabbed needles deep into his own body and lit himself on fire for sexual pleasure, seemingly in ways that others were able to observe and provide describe. When he was captured for his crimes, authorities found around 30 needles in Albert Fish's X-ray. We'd like to think that a person exhibiting similar behavior would catch the attention of concerned parties before they started killing.

Ted Bundy had an odd early life, but those unusual elements have been overshadowed by his later activities. Born to a 22-year-old single mother, Bundy never knew his father and almost grew up without his mother. She considered giving Bundy up for adoption but later decided to move with him to her parents' house, allowing the boy's grandparents to raise him as their own. Bundy grew up believing that his mom was his sister and his grandparents were his parents. Many have connected his feelings of rejection by his mom with his eventual killing spree, but he showed some early signs of unusual behavior.

While living with his grandparents, Bundy also shared space with his 15-year-old aunt, Julia Cowell. One morning, Cowell awoke to find 3-year-old Bundy lifting up her bedsheets and surreptitiously inserting butcher knives into her bedspread with a grin on his face. Cowell addressed this incident, which may have occurred more than once, but no one else in the family shared her concern. She claims that no one else even thought placing knives around someone's sleeping form was weird. While Cowell certainly noticed that red flag, the rest of Bundy's family ignored the incident until his eventual arrest.

Jerome Brudos, like many future serial killers, received forgiveness for his first unforgivable act. Born in South Dakota, Brudos had a difficult relationship with his mother, who frequently lorded over him. He allegedly developed an early fascination with women's footwear that his mom tried to stop. His mom met his pubescent sexuality with disgust and rage, forcing him to hide his carnal urges and grotesque fantasies. At 16, Brudos stole a woman's undergarments then kidnapped and assaulted her to force her to pose nude for photographs. Though she escaped and informed the police, Brudos launched another similar attack before they got him.

At 17, Brudos lured a girl his age into his vehicle, brought her to an abandoned farmhouse, and beat her repeatedly. A passing couple discovered Brudos and informed the police, though Brudos attempted to convince them that he was also a helpful bystander. The cops saw through his ruse and charged him with assault and battery, eventually landing him in Oregon State Hospital for evaluation. Despite his crimes, the hospital allowed Brudos to continue his high school education while receiving treatment. They dismissed him after less than a year, determining that he wasn't a danger to society. They were proven wrong years later, when Brudos' crimes escalated to four murders.

Some would probably look at John Wayne Gacy in his clown outfit and see a red flag, but it was far from his only obvious sign. There was something inherently unassuming about Gacy that seemed to disarm the communities around him, making it almost impossible for them to suspect him of wrongdoing. In 1967, two teen boys informed the police that Gacy plied them with alcohol, forced them to watch pornography, and attempted to molest them. Gacy attempted to hire muscle to keep them quiet but still caught a 10-year sentence on sexual assault charges. He served only 18 months and stepped back into civilian life in 1970.

Shortly after his release, another teenager ran to the police, accusing Gacy of attempting to sexually assault him. Those charges were dropped after the alleged victim refused to appear in court to testify, which meant Gacy narrowly skirted a parole violation that would have put him back in prison. Even though Gacy had twice faced accusations of sexually assaulting a minor and received a conviction, he didn't immediately become a suspect when teens started disappearing in his area. Gacy started killing in 1972, less than a year after his second trial, but cops didn't home in on him as the perpetrator until complaints motivated a stake-out in 1976. 

If you or anyone you know needs help with addiction issues, may be the victim of child abuse, or has been a victim of sexual assault, contact the relevant resources below:

• The Substance Abuse and Mental Health Services Administration website or contact SAMHSA's National Helpline at 1-800-662-HELP (4357).

• The Childhelp National Child Abuse Hotline at 1-800-4-A-Child (1-800-422-4453) or contact their live chat services.

• The Rape, Abuse & Incest National Network website or contact RAINN's National Helpline at 1-800-656-HOPE (4673).