Crime Library: Criminal Minds and Methods

Serial Killer Myths Exposed

Signature is the mark of a serial killer

I can count on one hand the number of signatures I have seen in the serial murders I have worked, and I think I am probably exaggerating. Signature is extremely rare, and the belief that it commonly exists confuses police investigators and makes for a lot of foolish assumptions.

What does signature mean? Supposedly these are the added touches that make the crime personal to the killer. I am not sure what exotic added touch the killer left at a crime scene where the woman was found strangled under a bush. Or drowned in a bathtub. Or buried in a national park. On occasion, a serial killer will want to horrify the police or public passing by and will pose the body on the side of the road in some shocking position or do some other insult to the victim's body with cutting or writing or object insertion. Rarely do they leave notes, but, when they do it is their way of mocking society and law enforcement. Most of the time killers hit victims over the head, rape them, strangle them, and leave them wherever they drop. It usually happens very quickly. There are only a small percentage of serial killers who make the effort to imprison their victims and torture them. Women who kill their children, nurses who kill their patients, and shooters who randomly shoot their victims from afar don't employ any obvious personal touches when they kill. Signature is just some fancy way for nonserial killers to imagine how serial killers feel about their killing.

The kinds of signatures we see in the movies are always very clear. Each victim has something done to them. This helps in linking those cases to a particular serial killer in a way we almost never see in real life! Wouldn't it be nice if the French Fry killer stuffed french fries in every victim's mouth and the Smiley Face killer drew a smiley face on the victims' abdomens? This would be very useful. Unfortunately, it doesn't happen like that and because it really doesn't, profilers and psychologists will claim that signature is not that obvious but it is more of a feeling one gets at each of the crime scenes that signify one killer is at work. Signature is usually described after the serial killer is caught because no one knows what it is until after the homicides are analyzed. Confused? I am.

On rare occasion a serial killer will have a fetish that is mistakenly called a signature. Roger Kibbe, a serial killer active in the 1980s in northern California, liked to do what is called nonfunctional cutting of women's clothes. He was not "signing" his work; he was just enjoying himself in a way which turned him on. These fetishes can indeed be useful for linking certain serial homicides, but I still wouldn't call them signatures.   It is too bad so many serial killers are rather boring and don't have any outstanding oddities to make investigation easier.

What would Bobby Joe Leonard's signature be? I don't know. Maybe that he likes to put women in closets because that makes the crime personal to him. No, maybe that is just his MO, which includes the elements of the crime that are necessary to accomplish it. Did he put women in closets because it was his unique way of finalizing the crime? "Ta-da! Bobby Joe finishes his work and closes the door!" Signature? Or did he just think it was a good idea to hide the bodies and delay discovery, which would be part of his MO? This brings us to the next confusion.

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