THEY say you should never return to the scene of a crime, but what about being so confident that you leave a distinctive calling card?

From scrawling mysterious pentagrams on their victims to even sending anonymous letters to the police, some of the most NOTORIOUS serial killers in history left chilling calling cards.

While cases of serial murder and even cannibalism aren't all that uncommon, the fearless nature of these symbols will send a shiver down your spine.

Scarily enough, some of these murderers were never caught and remain at large...

BTK's Signature

8 Dennis' calling card eventually resulted in his arrest

American serial killer Dennis Lynn Rader, the BTK killer, brutally murdered TEN people between 1974 and 1991 and took trophies from each of them.

His death toll could have been higher too - Anna Williams, 63, only escaped being one of his victims when she got home later than she meant to in 1979. Chillingly, he admitted feeling "absolutely livid" when she escaped as he was obsessed with her. He spent hours outside her home, but eventually left because she was so late back.

After revelling in the fact that he hadn't been caught in over 10 years, Rader sent taunting letters to the Kansas police, all signed with his infamous signature BTK.

The letters, arranged to look like a female figure, represent the cold-blooded killer's methods: blind, torture, kill.

8 The letters BTK form the shape of a female figure

As no one had ever known about the secret signature, police were able to identify Rader and he was sentenced to life imprisonment in 2005.

The Zodiac's Letters

8 The Zodiac killer's identity remains a mystery

While BTK's creepy signature ultimately led to his arrest, it was a different story for the Zodiac killer.

His calling card, a circle with a cross through the middle, similar to a target, was sent to newspapers in all the areas where the murders had taken place along with cryptograms that included unreleased details of the murders.

8 The calling card resembles a target

It is certain that the northern Californian-based Zodiac Killer, murdered four men and three women all under the age of 29.

However, he has claimed to have killed 37 people.

Shockingly, the brutal murderer has never been identified and many of his cryptograms remain a mystery to this day.

The Beltway Snipers' Tarot Cards

8 The tarot cards read "Call Me God"

In October 2002, residents of Maryland and Washington D.C. were frozen with fear during the Beltway Snipers' three week killing spree.

The attacks included a series of coordinated shootings near petrol stations and roadside services.

The Death Cards of the Tarot deck were found at the scenes of the crimes with the eerie words "Call me God."

These haunting calling cards sparked mass fear in North America, with people trying to avoid being outside and some schools even closing.

Long handwritten letters, threatening violence against local children were also uncovered, but thankfully, after a huge manhunt and investigation, John Allen Muhammad and Lee Boyd Malvo were brought to justice.

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The Night Stalker's Pentagram

8 Richard flashes the pentagon symbol to the jurors Credit: Bettmann

Richard Ramirez, the infamous Night Stalker, used a pentagram as his calling card.

Drawn in his victims' lipstick, Ramirez' trademark symbol was found drawn on walls, mirrors and even the thigh of Barbara Pan who was sexually violated by Ramirez before being shot in the head.

In murdering the 79-year-old Jennie Vincow, he slashed her throat so deeply that she was almost decapitated.

The true identity of the Night Stalker was eventually uncovered and Ramirez was convicted of 13 counts of murder and 5 counts of attempted murder, along with 11 counts of sexual assault and 14 counts of burglary.

When Ramirez was taken to court, he explained that the pentagram symbolised his love of Satan.

The killer flashed a pentagram to the petrified jurors saying "Hail Satan," before he was sentenced to death row where he lived until he died of cancer in 2013.



Jack the Ripper's Letters to Police

8 Jack the Ripper's letter was headed "From Hell"

The brutal murderer responsible for the unsolved serial murders in London in 1888 created his own name when he signed letters to the police as Jack the Ripper.

At first the letters were thought to be a hoax, but due to its timing it is now believed to be genuine.

One of the most famous letters is known as the "From Hell" letter and which arrived in a chilling box that contained a piece of preserved human kidney.

The serial killer's victims were generally poor, female prostitutes working in the slums of the East End.

Jack the Ripper would slice the women's throats before their inner organs were removed and mutilated, this has led the figure to become a solidified legend.



The Happy Face Killer

8 Jesperson was eventually brought to justice

The trademark smiley face calling card of Keith Hunter Jesperson was left on a confession letter of a bathroom wall of a truck shop.

In this creepy letter and those subsequently sent to the police, he confessed to having killed as many as 160 people.

Despite his horrifying confessions, he was only confirmed to be tied to the murder of eight people.

However, this still left him serving three consecutive life sentences for his brutal killings that spanned across half a decade.

Just like Jack the Ripper, many of his victims were also prostitutes who he raped before strangling them.