The "Signature" Aspect in Criminal Investigation

By Vernon J. Geberth, M.S., M.P.S.
Former Commander, Bronx Homicide, NYPD

©1995 Vernon J. Geberth, Practical Homicide Investigation
LAW and ORDER Magazine, Vol. 43, No. 11, November 1995

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The signature aspect of a violent criminal offender is a unique and integral part of the offender's behavior. This signature component refers to the psychodynamics, which are the mental and emotional motivations. Essentially, our human sexuality is established during our psychosexual development through conditioning and experience. Sexual behaviors, both healthy and unhealthy, are learned behaviors in which the individual develops a perception of what is sexually stimulating and satisfying.


Clinically speaking, there is a behavioral distinctiveness in human sexuality. This unique aspect of our sexual arousal and response system accounts for why individuals differ in their sexual behaviors. In sex-related criminal incidents the offender is oftentimes subconsciously "acting-out" a sexually significant behavioral pattern, which reflects the underlying personality, lifestyle, and developmental experiences of the offender. According to Dr. John Money (1986) there is a kind of love map depicting an idealized lover, love scene, and a program of erotic activities. These are related to the natural human development of the individual and are influenced by both biological aspects as well as the environment; nature and nurture. Sexual deviation occurs when these lovemap" patterns become derailed. Child molesters, rapists, deviant murderers and others with peculiar erotic interests are an example of this phenomenon.

The formulation of sexual deviance can usually be traced to aberrant erotic development. For example; strict anti sexual upbringing, sexual abuse of a child by the primary care giver between the ages of five and eight, overexposure to sexually stimulating behaviors and/or inappropriate and pathological family dynamics.

Human behavior, although unpredictable, is oftentimes repetitive. Research has indicated that certain actions engaged in at the homicide crime scene by certain types of personalities will repeat themselves in other homicide investigations. The homicide detective, who has enhanced his experience with a comprehension of the psychodynamics of human behavior, will be able to develop a base of knowledge, which can be applied to the review of similar cases.


From an investigative perspective, it is important to note that these individualistic behaviors are learned behaviors, which tend to remain consistent. An offender's M.O., or "method of doing things" is also a learned behavior. However, these type behaviors are developed over time and change as offenders gain experience, build confidence or become involved with the criminal justice system. The "signature" component may also change to some degree. However, the change usually involves a progression of violence and sexual mutilation, which is consistent with the paraphilia Sexual Sadism as seen in lust murders. The M.O. involves actions necessary to accomplish the activity while the 11signature aspect" represents the underlying emotional "needs" of the offender. These "needs" usually present as behaviors and actions that go beyond those necessary to accomplish the crime. When dealing with an offender, who is a sexual sadist, one can expect to see a progression of violence as the series evolves. Understanding and recognizing both the modus operandi and the signature aspect of the event can enable the professional investigator to "link" events in a series.


Linkage blindness is defined by the author as an investigative failure to recognize a pattern which "links" one crime with another crime in a series of cases through victimology, geographic region or area of events, the "Signature" of the offender, similar M. 0. and a review of autopsy protocols.


When an offender displays behavior within the crime scene and engages in activities, which go beyond those necessary to accomplish the act he is revealing his signature. These significant personality identifiers occur when an offender repeatedly engages in a specific order of sexual activity, uses a specific type of binding, injures and/or inflicts similar type injuries, displays the body for shock value, tortures and mutilates his victim, and engages in some form of ritualistic behavior.

In the "Vampire Killer" case, ( Law and Order, June, 1991) the killer was targeting young women, whom he would eviscerate. Investigation revealed that the offender was removing blood and body parts from his victims. The sexual motivations were obvious in the mutilations. The other activities engaged in by the offender were so absurd and bizarre that authorities were immediately able to link the incidents. However, the motivation underlying these series of crimes appeared totally irrational.

The offender, who was seemingly unconcerned about apprehension, left an abundance of physical evidence at his crime scenes. The detectives properly focused their investigation on someone who would be described as a psychotic or disorganized individual. One of the most common signatures is that of the psychopathic sexual sadist, who involves himself in complete domination of the victim. The author has reviewed and consulted on a number of serial murder cases that have revealed this signature aspect of the crime.


Timothy Spencer, who was responsible for the sexual murders of four women, was a cat burglar and rapist who stalked his victims. He was able to enter their homes while they were asleep. In fact, in the Chesterfield County case, he was able to access a 15-year-old victim while her parents were asleep in another part of the house. In the other three cases, he made sure that the victims, who were married or had a relationship, were home alone when he attacked. He exerted total control over these victims and spent considerable time in their homes. His behavior with the victims and his actions in the crime scene indicated that he was a classic sexual psychopath.

The prosecution of this offender was based upon the "Signature Crime Theory." In each of the incidents the women, had been raped and sodomized by their attacker after he had accosted them in their sleep. Each victim had been strangled to death with ligature. Each of the victims were found face-down and had been similarly bound with their hands tied behind their backs.


A series of murders occurred within Washington State in 1990. The murders began in Bellevue, Washington in June and ended within King County in September, 1990. Initially, authorities were not aware of the linkage of these cases, due to a delay in the analysis of pubic hair evidence retrieved from the first two crime scenes. In addition, the authorities were misdirected with the emergence of a more viable suspect in the second murder investigation. However, when the evidence analysis of the hair had been completed and the initial suspect eliminated, the authorities were presented with a classic "Signature-type" series of events.

It is important to note that in the real world of conducting an active homicide investigation, we don't have the luxury of "retrospective knowledge." Many alleged "experts", who criticize police investigations are "smart" after-the-fact, when ALL of the information is finally available for review. When you examine this case chronologically, and assess the information that authorities had at the time they were conducting their inquiry, one can understand how these cases were not initially linked.


The first victim was a 27 year-old, white female, whose nude body had been discovered in the parking lot of a restaurant on June 23, 1990. Her body was found, face-up, lying on her back with her legs crossed at the ankles. Her face was partially covered with a lid from a plastic cup, which covered blunt force injuries to her head. There was also evidence that her necklace had been used as a ligature along with scratch marks on the side of her neck. In addition, there were post mortem drag marks on the high points of her body, indicating that she had been dragged. The assailant had posed the victim's body with the victim's hands crossed on her chest with a pinecone beneath her fingers. The police recovered foreign pubic hairs on and near the body. The medical examination revealed that she had been vaginally raped and anally sodomized with an unknown object. Her clothing was missing along with any identification. As a result, her identity remained unknown until June 27, 1990 when she was identified as a "Missing Person" from Redmond, Washington. She had last been seen in the early morning hours of June 20th at a popular bar and restaurant. Her car was later located in the parking lot of the establishment where her pocketbook was discovered in the restaurant's Lost and Found.

Signature Aspect

A body of a nude female, who had been sexually assaulted (raped and anally sodomized with an object), and then posed with a prop (the pinecone) beneath her hands. The body had been positioned so that the victim was lying on her back face up, thereby exposing her breasts and genitalia. Semen and sperm were recovered along with unknown pubic hairs. This pointed towards an organized offender, who was able to "con " the victim away from a safe area. She was raped at one location and then deposed of at another location. Her body was displayed for shock value and her clothing was taken to hinder identification.


The next case also occurred within the City of Bellevue. On August 9, 1990, the body of 32-year old white female was discovered in her bedroom by her 13-year-old daughter. The victim's nude body had been displayed on the bed with a pillow over her head. The barrel of a shotgun had been inserted into the victim's vagina. The body was totally nude except for a pair of red high heel shoes, which had been placed upon her feet by the offender. The body had been positioned so that whoever walked into the room would be confronted with this grotesque sight. There was evidence of blunt force trauma to the head and manual strangulation. Although there wasn't any evidence of vaginal rape or sodomy, there were foreign pubic hairs found on the mattress and the rug in the victim's bedroom. Two expensive rings were missing from the hands of the victim.

Signature Aspect

A body of a nude female, who had been sexually assaulted (The victim was nude, object inserted into vagina foreign pubic hairs), was found in her residence. There wasn't any evidence of forced entry. The body had been displayed and then posed with props (insertion of the shotgun into the vagina and the red high heel shoes on her feet.) Foreign pubic hairs were retrieved from the crime scene. The offender had managed to enter her home, assault and kill her and then spend a considerable amount of time in the crimes scene as he engaged in unknown conduct with the body. The body was face-up exposing her breasts and genitalia and posed for shock value. The injuries to this woman's head were more extensive and the posing more degrading then victim number #1 Two expensive rings were stolen from the victim's hand.

NOTE: However, in this case the police had good reason to suspect a former boyfriend, who made an excellent suspect due to his activities prior to the murder. In addition, when the police attempted to question him, he hired an attorney, who refused to even discuss the case with the authorities. The pubic hair from the first case as well as the present case was not analyzed until September. In fact, this case, as presented to authorities, appeared to be a classic interpersonal violence oriented type dispute and assault.


The next case took place within King County. The body of the 24-year-old, white female victim was discovered in her bedroom on September 3, 1990. Her nude body had been positioned under the bed covers with a pillow covering her face. There was a vibrator placed in the victim's mouth and next to her head was a book entitled "More of the Joys of Sex." There was also evidence of blunt force trauma to the victim's head. When the police removed the bed covers, they saw that the body had been placed spread-eagled on her back, with a series of postmortem slashing and stabbings. The victim's body was face-up thereby exposing her breasts and genitalia. Crime scene technicians recovered a foreign pubic hair, which was adherent to one of her stab wounds.

There was evidence that the offender had spent considerable time in the crime scene. The cause of death was blunt force trauma to her head. However, the offender felt the need to inflict over 240 post mortem stab wounds throughout the victim's body. There were frontal wounds into the side of the victim's neck, into her chest, breasts and abdomen, and upper thighs. There were a series of dorsal wounds into the back and buttocks, and along both legs. Even the bottom of the victim's feet bore evidence of this piquerism. An expensive ring was missing from the victim's finger.

Signature Aspect

A body of a nude female, who had been sexually assaulted. (The victim was nude, piquerism, foreign pubic hairs), was found in her residence. There wasn't any evidence of forced entry. The body had been sexually displayed and then posed with props (insertion of the vibrator in the victim's mouth and the book, "More of the Joys of Sex " placed nest to her head) A foreign pubic hair was recovered from her body. The offender had managed to enter her home, assault and kill her and then spend a considerable amount of time in the crimes scene. The infliction of over 240 postmortem wounds throughout the body took a considerable amount of time. The offender had degraded the victim in death and had posed the body for shock value. The injuries to this woman's head were much more extensive and the posing, with the vibrator in her mouth, more degrading then victim number #2. A ring was stolen from the victim's hand.


The suspect was a 33 year-old black male. He was a known burglar, who as an adolescent had a history of fetish burglaries and other nuisance offenses. He was developed as a suspect when he was found in possession of a gun, which had been taken from a residence nearby to the last homicide. The pubic hairs recovered from each of the crime scenes were Negroid in origin and were found to match the suspect. The subject, who was a police buff, was fascinated with police work. He had police scanners, and told people he worked for the police and the FBI. He was also fascinated with serial murder cases and reportedly was well read on the Ted Bundy and Green River cases. He followed the news stories very closely and had cut out the news stories as well as the photographs of the victims. He would compare them to each other and ridicule the police techniques. He had stated to friend, "that the only way the police will catch the killer is with trace evidence."


Each of the bodies had Negroid hairs on or near their bodies. The semen and sperm found on the first victim was matched to the suspect through DNA. The police located a vehicle used to transport the first victim and discovered blood in the front seat cushion. This blood was matched the first victim through DNA analysis. Police located a witness who identified one of the rings stolen from the second victim. The suspect had tried to sell the ring to the witness. The ring stolen from the last victim was traced back to the suspect.


Each murder was sexually motivated. Each of the victims were discovered totally nude. Each victim's body had been positioned face-up to expose the breasts and genitalia. Each victim had been posed and/or positioned after death with props and/or objects inserted near or placed on their bodies. It was apparent that the killer spent a considerable amount of time with each of the victims and engaged in activities, which went well beyond those necessary to kill the victims. In fact, there was a classic progression of violence inflicted on each new victim. The cause of death for each of the victims was blunt force trauma. In each case, trophies had been taken from the victims, i.e. clothing, rings, jewelry. Each crime scene revealed Negroid pubic hairs, suggesting a black offender.


The homicide detective, who has enhanced his or her experience with a comprehension of the psychodynamics of human behavior, will be able to develop a base of knowledge, which can be applied to the review of similar cases. The ability to "read" the crime scene and recognize the "signature" of an offender can be extremely instrumental in the investigative process.

© Vernon J. Geberth. Lt. Cmdr. Geberth is a nationally renowned authority on homicide investigation. This article is revision matter from his textbook, PRACTICAL HOMICIDE INVESTIGATION: Tactics, Procedures, and Forensic Techniques.

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