Crime Library: Criminal Minds and Methods

The Clairemont Killer

Signature Killer

An offender's method of perpetrating a crime is indicative of certain aspects of his personality; what he may leave behind as a personal stamp — a behavior that was not necessary to accomplishing the crime — shows others. An MO may change as the offender learns and perfects his crimes, but his signature tends to remain static. The MO is learned behavior, while the signature arises from personality traits and deviant compulsions.

"When I start analyzing research into the minds and motivations of serial killers," said Douglas in an interview, "I would look for the one element or set of elements that made the crime and criminal stand out, that represented what he was."

Considering the differences in the Clairemont-area series, the only victim stabbed only once had been followed and subdued via the same MO as in the other crimes. The assault had been interrupted so it was not clear whether the perpetrator might have continued. In every other way — victim type, time of day, weapon used — it was similar. Only one victim had been sexually assaulted, while only one had been covered after the attack. One victim — the dancer — was higher risk than the others. However, taken all together to determine the links, the similarities outweighed the differences.

"There is simply no way," said Douglas, "of coming up with a numerical value for each piece of information. It can be properly evaluated only by running it though the brain of an experienced profiler." Ankrom and Douglas decided that the motive for all six murders had been controlled sexual rage. They weren't alone in this interpretation.

Former Investigator Robert R. Keppel
Former Investigator Robert R. Keppel

Former investigator Robert R. Keppel included this series of murders in his book, Signature Killers, because the offender left such a distinct behavioral signature at five of the murder scenes. "Almost all sex offenders, especially signature killers," Keppel states, "need to demonstrate a degree of total control over the victim, whether she's living or dead. They have to; anger drives them to do it."

Book Cover: Signature Killers
Book Cover: Signature Killers

Although Prince had explained to one of his accomplices in burglary that a stab to the heart was the surest way to kill, Keppel saw the multitude of stab wounds as a form of deviant sexual behavior known as piquerism. That is, Prince enjoyed stabbing and gouging with a sharp implement. In particular, he aimed at the heart and left breast, stabbing deeply many times — more than was necessary to kill. Keppel's signature analysis, which noted both the overkill and the ritual involved, indicated that he was angry and felt a need to control his victims. It was also sexual.

He was stimulated by violence and since only one victim had been raped, Keppel suggests that the knife was a substitute for penile penetration. Keppel believed that Prince was a sadist, having sunk the knife in slowly, with satisfaction. In fact, he'd stabbed to the depth of an erect penis. "The killer was obsessed with the stimulation of penetrating the victims," Keppel adds. Prince left the knife behind at three scenes to "show" the police his prowess. Keppel indicates that Prince's primary pleasure came from seeing blood flow from a woman's breast.

But how did Prince actually measure up?


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