Any horror fan worth their salt will tell you that a film somehow becomes instantly more frightening when you learn that it’s based on a true story.

To that end, then, we’ve rounded up some seriously scary movies, all of which are inspired by real life serial killers, murders, and (sometimes still unsolved) true crime cases.

Fair warning, though: you’re going to have more than a few sleepless nights after watching even one of them.

Scream

That’s right, the iconic 90s slasher film is loosely based on true events. In 1990, Danny Rolling – aka the Gainesville Ripper – went on a murder spree, killing five students over the course of four days. All were ambushed and murdered in their own homes, and all were killed with the same murder weapon: a knife.

After his arrest, Rolling also confessed to an unsolved triple murder in Shreveport, and was sentences to death for his crimes. He was executed by lethal injection in 2006.

Screenwriter Kevin Williamson explained to CNN that he was sitting in his living room watching a news item on The Gainesville Ripper, and it scared him so badly that he became inspired to write Scream.

“I was watching this Barbara Walters special on the Gainesville (Florida) murders, and I was getting so spooked,” he said.

“I was being scared out of my mind. During the commercial break, I heard a noise. And I had to go search the house. And I went into the living room and a window was open. And I’d been in this house for two days. I’d never noticed the window open. So I got really scared. So I went to the kitchen, got a butcher knife, got the mobile phone. I called a buddy of mine… [and I started writing the script for Scream].”

The People Under The Stairs

In this critically-acclaimed horror, a young boy breaks into the home of his family’s greedy and uncaring landlords, only to discover that they a) are incestuous psychopaths and b) have mutilated a number of boys and are keeping them imprisoned under stairs in their large, creepy house. Will he be able to escape before it’s too late?

Wes Craven previously said the film is inspired by a true crime case from 1978, when a pair of burglars forced their way into a home in Los Angeles. When the police showed up, they made a shocking and unrelated discovery: the couple living in the home had locked their two children in the basement of the home.

The Sacrament

This found-footage horror film details the events surrounding an investigative team’s visit to a remote commune, led by a dangerous fanatic who maintains an iron grip on his followers.

It’s a shocking film, with a particularly horrifying ending. And it’s made even more so when you reconcile yourself to the fact that it’s based on the 1978 Jonestown Massacre, which saw over 900 people drank spiked grape-flavoured Kool-Aid, result in a mass murder-suicide.

The Texas Chainsaw Massacre

In 1968, Ed Gein – known in the papers as ‘The Mad Butcher’ – was found guilty of murdering at least two women, and mutilating the bodies of nine others. 

Perhaps even more disturbing than this, though, was the fact that Gein had used the skin of his victims to craft everything from shoes and wastepaper baskets, to a ghoulish mask.

This horrifying detail provided the inspiration for ‘Leatherface’, the terrifying maniac at the centre of The Texas Chainsaw Massacre. And thus explains the gory film’s chilling tagline: “Based on true events.”

Psycho

While we’re on the subject of Ed Gein, it’s worth noting that the serial killer also provided the inspiration for Alfred Hitchcock’s Academy Award-winning horror film, Psycho – or, rather, the inspiration for the book upon which the film is based.

Much like Psycho’s Norman Bates, Gein was raised by an oppressive mother and developed a morbid fascination with the female body after her death. And, turning to grave-robbing, he began seeking out the bodies of women who were roughly the age of his mother at the time of her death.

In 1968, Gein was found guilty but due to his mental state, he was put into a psychiatric institution. As local newspapers pored over the details of the disturbing case, it caught the attention of author Robert Bloch, who lived less than 50 miles from the killer’s home – and so the frightening character at the centre of Psycho was born.

Veronica

Set in 1991 Madrid, Netflix’s Veronica follows a teenage girl of the same name, who uses an Ouija board to make contact with her best friend’s late boyfriend during a solar eclipse.

In typical horror fashion, though, things don’t go to plan: Veronica (Sandra Escacena) ends up contacting her dead father instead. At the exact moment of the eclipse, the glass cup used during the séance shatters and cuts Veronica’s finger, causing a drop of her blood to fall onto the Ouija board itself. The teen lets out an inhuman cry before passing out and, from that point on, seems marked by an evil supernatural force – one which, at one point, takes on the appearance of a cigarette-smoking nun.

So far, so horrifying. What adds to Veronica’s creepy charms, though, is the fact that it is based upon a true story.

In 1992, a young girl named Estefania Gutierrez Lazaro organised a séance at school in order to contact the late boyfriend of one of her friends. Some six months after the séance, however, Lazaro was found dead, the cause of which remains unknown.

Her parents, though, said they thought that her passing had something to do with the Ouija board, and claimed that their house became haunted after Lazaro’s passing: they experienced slamming doors, electrical appliances switching on and off, and a mysterious whispering. And these phenomenon were verified by police reports, too.

As Newsweek outlined, there were “three officers and the Chief Inspect[or] of the National Police, Jose Pedro Negri” witnessed an armoire door opening on its own and “a crucified Jesus separated from his cross and a large, brown stain, attributed to drool.”

The Strangers

“Why are you doing this?”

“Because you’re home.”

There’s nothing more unsettling than a sharp knock at the door in the middle of the night. Nothing, of course, except a sharp knock at the door from a trio of masked strangers in the middle of the night.

Thus begins The Strangers, one of the most shocking and brutal horrors in recent history. And, according to writer and director Bryan Bertino, the film is primarily based on two different true crime cases.

The first is, of course, the infamous series of murders committed by the Manson Family in 1969, particularly the home invasion and killing of Sharon Tate. The second, though, is the 1981 Keddie Cabin Murders, in which four people were killed in a small California resort town.

Their killers were never caught, the motive was never uncovered, and the case remains unsolved to this day.

The Exorcism Of Emily Rose

This supernatural horror film is loosely based on the story of Anneliese Michel, a young a German woman who underwent 67 Catholic exorcism rites during the year before her death in 1976.

When Michel was 16, she suffered the first of many seizures. As the years went by, she was also diagnosed with depression and temporal lobe epilepsy. However, when doctors and a series of medications failed to improve her symptoms, Michel’s family became convinced she was possessed by a demon.

Over the course of 10 months, 67 rites of exorcism were performed on Michel, which proved difficult on her body. As a result, she began to refuse food and water, but doctors were never called. No longer able to move without assistance, she died at home as a result of malnourishment and dehydration, and her parents and priest were convicted of negligent homicide.

Wolf Creek

Between December 1989 and April 1992, seven young backpackers went missing while hitchhiking between Sydney and Melbourne in Australia. Their bodies were all discovered in the Belanglo State Forest.

It wasn’t until 1996 that serial killer Ivan Milat, referred to as The Backpacker Murderer by tabloid newspapers, was convicted of the murders. 

Wolf Creek was released in cinemas in 2005, and self-advertised as being based on true events. Indeed, the opening sequence of the movie states: “30,000 people are reported missing in Australia every year. 90% are found within a month, many are never seen again.”

Revolving around three backpackers who find themselves taken captive in the Australian outback, the parallels between the plot and the case of The Backpacker Murderer is clear to see – although it also took inspiration from murderer Bradley John Murdoch, who is currently serving life imprisonment for the July 2001 murder of English backpacker Peter Falconio.

The Hills Have Eyes

We all know the story by heart: a wholesome suburban family are driving through the Nevada desert on a road trip, when their car breaks down unexpectedly and leaves them stranded. Stranded and, we hasten to add, at the mercy of a clan of cannibal savages. 

The Wes Craven movie was apparently inspired by Sawney Bean, a Scottish man who, according to legend, led his clan to kill and eat 1,000 people around the year 1600.

It’s worth noting, though, that a Scottish historian recently told the BBC that the legend was most likely a damning fiction created by prejudiced Englishmen “as a dig at Scots.”

Images: Getty/Netflix