While “calling card” has a context in crime, the term has its origins in an 18th century social practice. Often, those in the upper class would have personalized cards that they would leave at the homes of friends and family who were away. This was done as a way to inform others that they’d been by for a visit. But this nicety adopted by society was also usurped by criminals who similarly wanted to leave their signature on an offense or leave behind a token unique to them. This also became known as their calling card. In the same way as a traditional calling card, a criminal calling card is used to ensure the police know who committed the felony. While calling cards don’t typically expose the exact identity of the perpetrator, they are a purposeful way for a single criminal to claim responsibility and mock the police.
Not all criminals who use calling cards are serial killers, but serial killers often leave the more gruesome and frightening of them. In fact, earlier laws around serial killings in the U.S. specified that the murders must have “common characteristics such as to suggest the reasonable possibility that the crimes were committed by the same actor or actors.” Every serial killer has an M.O., but some go beyond just the necessities of a murder—going out of their way to do something extra at the scene of the crime, which becomes their calling card. While this isn’t always used today, it is considered important to the investigation. A calling card that links several murders can help develop investigative theories around a killer’s motive and criminal profile.
Some calling cards are more subtle than others, but many high-profile cases are well known due to the calling cards associated with them. Some have even had calling cards so iconic that they’ve encouraged “copycat killings.” Examples include the Zodiac Killer, the Night Stalker, and the D.C. Beltway Sniper. Each of these killers left various symbols or signs at the scene of their crimes, typically directed at the police. There are several theories behind why killers do this, when communication with police may increase their chances of being caught. Some speculate the root cause to be a killer’s narcissism and belief that he or she can get away with murder no matter what clues they leave behind. Others theorize that it’s a guilt reaction, where a killer knows they’re doing wrong and wants someone to stop them. Others think it’s as simple as wanting to gain notoriety. Lastly, calling cards that aren’t directed at the police per se may be a way of heightening the fantasy-fulfillment that serial killers get through committing their crimes.
There is still a lot that investigators and psychologists don’t understand about serial killers. For every theory there seems to be a counter-theory. The mystery and debate surrounding calling cards is an example. This is, perhaps, the reason why calling cards continue to be the subject of much fascination in pop culture—be it fictional or the very real, unfortunate stories of victims.