Wesley Shermantine and Loren Herzog grew up in the California countryside, hunting for deer and elk. In high school, they turned to methamphetamine to recreate the thrill they once got from hunting. But as their drug use intensified, they needed something stronger to maintain their high. They needed to kill, and this time, their prey was human.

At a young age, Mikhail Popkov developed a deeply misogynistic view of the world. As an adult, he used his power as a police officer to act on these feelings, murdering women he deemed to be morally defunct.

Police had taken Roger Kibbe into custody numerous times but never had enough evidence to arrest him. Each time he was let go, he went on to claim more victims. But a discovery by a forensics investigator was exactly what authorities needed to put him away for good.

After killing his first victim, Roger Kibbe decided to keep a low profile. But years later, his urge to kill returned. By mid-July of 1986, he had killed four young women — three of them in the past three months. And he had no intention of quitting.

Roger Kibbe spent most of his adolescence filled with rage. And while he had a long list of arrests by his mid-30s, it was never for violent crimes. Until one day in 1977, he finally snapped.

In 1946, the mysterious Phantom Killer who had terrorized the town of Texarkana for months disappeared just as quickly as he'd appeared.

In 1946, the city of Texarkana was plagued by a series of attacks and murders on couples parked in their cars. Police, however, failed to act quickly enough, potentially giving the murderer enough time to get away.

As a child in the ‘80s, Matthew Macon was thrust into a world of chaos and turmoil. From a young age, he was in and out of federal institutions, but nothing seemed to curb his darker impulses. Eventually, he gave into them, and his killing spree began.

Viktor Sayenko and Igor Suprunyuk were insecure children, scared of the world around them. As teenagers in the 2000s, they pushed themselves to move past their fears. But in the process, they unlocked something even more terrifying: an uncontrollable desire to kill anything and anyone.

Glennon Engleman had claimed two lives during his insurance fraud schemes and escaped police detection with ease.

Glennon Engleman seemed like your average neighborhood dentist, but he was harboring a dark secret. He had a deep desire for money and power, and would do anything to get his way. Even kill.

He got a taste for killing while he was a soldier. But when the conflict between Iran and neighboring Iraq ended, his desire to kill remained.

In the early 1900s, a man lured his victims with lonely hearts ads, drained their blood, and stored their bodies in barrels filled with methanol.

Like many serial killers who get caught, Michael Bruce Ross became more reckless — attacking teenagers and young women in high-traffic areas, and often returning to where he dumped their bodies.

After experiencing severe emotional abuse as a child in the ‘60s, Michael Bruce Ross got a fresh start at Cornell University. But in his senior year, as his relationship with his fiancée began to unravel, he started acting out his perverse childhood fantasies — thrilled by the terror he could instill in his victims.

In the early 1980s, Larry Eyler haunted the highways of the Midwest, leaving the gay communities of Indianapolis and Chicago paralyzed with fear.

In the 1970s, Larry Eyler seemed like your regular, easy-going guy. Behind closed doors, he was anything but. He had an insatiable appetite to dominate. When BDSM wouldn’t do it, he hit the Midwest highways, offering desperate hitchhikers a ride and leaving behind a trail of dead bodies.

After serving his first prison sentence, Graham Young entered the world again, ready to start poisoning people once more.

Graham Young always had an obsessive personality, but when his father bought him a chemistry kit, it unlocked a terrifying interest in poisons. Before long, the teenager was poisoning mice just to see what happened. Then he set his sights on his best friend, and every member of his own family.

In 1981, Wayne Williams was a 23-year-old with aspirations of putting together the next Jackson 5. But after he’s found leaving the scene of a crime, he’s charged and convicted for two murders — and implicated in a dozen more.

In the late 1970s, a killer stalked the streets of Atlanta, Georgia, abducting and murdering young Black kids. The city was paralyzed with fear and theories abounded on the identity and motivation of the killer.

Todd Kohlhepp’s behavior was growing increasingly erratic. In the real world, he made unsettling comments to his employees and friends. Online, he continued posting a string of disturbing Amazon reviews. And on his private compound, he locked his victims inside a shipping container.

At 15, Todd Kohlhepp raped his 14-year-old neighbor, and 17 years later, he committed mass murder in broad daylight. Yet somehow, he became a pillar of society, building a successful real estate business from the ground up.

Benjamin Pedro Gonzales lived in a fantasy world. He’d imagine entire relationships that didn’t exist. And when his so-called “girlfriend” told him to get lost, he went into a murderous rage, leaving a horrific trail of dead bodies in his wake.

Joe Metheny tended to exaggerate and lie about his own life, but if half the atrocities he confessed to are true, he certainly earned his gruesome moniker.