Crime Library: Criminal Minds and Methods

Serial Killer Myths Exposed

You can link a serial killer to crimes by his MO

Method of operation (modus operandi/MO) has been another rather distressing concept in the investigation of serial killers. Perhaps when criminals commit other crimes they stay fairly consistent. For crimes you commit on a regular basis, say a couple times a week or maybe daily, it would be rather silly to reinvent your method of committing the crime each time you set out to do it again. If you found a good way to burgle a house, it makes sense to bring the same tools and repeat the previous steps.

Serial killers, however, don't kill very often. Really, they don't. Some wait years in between crimes and so when they do cross that line again they may fix something that didn't work last time or didn't feel right last time or didn't give enough of a thrill last time. A serial killer may decide to change from stabbing to strangling because last time he cut himself and he got too much blood in the car. He may decide he wants more time with the victim so he moves from an outside location to an inside location. He may decide to tie up the victim this time because the last one was hard to handle and it really ticked him off.

Using MO to link crimes can be problematic. If the MO changes within a series of homicides, the murders may not be seen as linked and a serial killer may go unnoticed. Gary Taylor is one such serial killer whose MO was all over the map. He started his criminal career by hitting women over the head with a wrench at bus stops. Then he started shooting women with a rifle. Next he chased women with a machete. He went on to using a ruse to get women out of their apartments. He would call up the victim and claim there was a fire at her place of employment or an emergency of some sort and attack her when she was getting into her car. He also posed as an FBI agent at the door of one of his victims. Near the end of his killing career, he kidnapped two women, tied them up in the basement, shot them in the head, and buried them in the backyard. Then he stopped killing and went about the country raping but letting his victims live.

Clearly Taylor's MO changed as his needs to control the situation changed. If one took MO to be a way to link these homicides together, one would end up with five different killers! Likewise, if one assumes that the use of the same MO signifies one killer, then the investigator runs into the opposite problem. Since there are only so many ways to kill a person, a good portion of homicides look pretty much alike. One group will be a bunch of strangled victims and another group will be a bunch of stabbed victims. A smaller group will be a bunch of shot victims. I guess there are just three killers out there for the entire United States.

Bobby Joe Leonard strangled Janie. He put her body in a closet. If there had been a next time, he might have liked cutting someone's throat. He might not have needed to put the victim in a closet if he felt no one would find the body for a long time anyway. It is difficult to know at this time if there actually were other victims in the past. Unless somehow he is linked to the proximity of another homicide or was an acquaintance of another murdered woman or DNA pops up to link him to another crime, we may never know for sure.

We're Following
Slender Man stabbing, Waukesha, Wisconsin
Gilberto Valle 'Cannibal Cop'