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First Murder: Behavioral Markers
In every serial killer’s life story, three categories of factors can usually be identified: predisposing factors (shaping personal vulnerability), facilitating factors (supporting the development of patterns of violence), and trigger factors (directly initiating criminal behavior). The first murder plays a key role in this dynamic. It acts as a catalyst, initiating profound transformations in the individual’s psychological structure and behavioral patterns. These changes are especially pronounced in cases where the crime remains latent – that is, undiscovered by law enforcement and unnoticed by the social environment – which contributes to the consolidation of the violent scenario in the offender.
John Douglas writes in his work: “The first homicide is often the most difficult for the offender to commit because of the psychological barriers that must be overcome. Once he has done it and gotten away with it, however, his inhibitions are significantly lowered, and he is more likely to kill again.” 1
The first murder represents a critical point in the development of a serial offender – a kind of “point of no return.” This is the event in which an individual first crosses the inner psychological barrier between aggressive fantasy and an act of violence. After this transition, the former identity collapses, and the offender enters a new behavioral phase characterized by repeated violence as an attempt to reproduce a sense of control and power and to resolve internal tension.
This event initiates deep, destructive transformations in the personality’s structure, laying the foundation for the subsequent criminal trajectory. From this point, the offender develops a stable propensity and drive toward the violent taking of other people’s lives, often combined with antisocial personality traits, destructive behavior, pathological narcissism, or psychopathy.
Many serial offenders display a pronounced dichotomy in their behavioral profile. At the level of personality structure, this manifests as a splitting of identity into a social “I” (externally adaptive, normative, integrated into social structures) and a hidden “I” (a concealed inner reality that contains the secret of the crime, dominated by fantasies of power and control over life and death, as well as associated feelings of anxiety and guilt). This split underlies the double life characteristic of many serial offenders. For them, the first murder becomes the “core” of the hidden “I,” the central event around which subsequent fantasies, ritual elements, and behavioral patterns consolidate. This hidden aspect of the personality is accompanied by chronic internal tension and anxiety caused by the constant risk of exposure.
As John Douglas and Mark Olshaker note, serial killers can maintain a socially acceptable pattern of behavior for many years while effectively concealing their criminal activity. This phenomenon, known in forensic psychiatry as the “mask of sanity,” occurs when individuals with antisocial or psychopathic traits imitate empathy, adherence to social norms, and emotional engagement. The hidden killer does this not for genuine integration but for manipulation, concealment of crimes, and survival in the social environment. In other words, he demonstrates such behavior as social camouflage.
A number of identifiable behavioral, psychological, and narrative markers emerge after the first murder and are predictive of the risk of recidivism, meaning a propensity for subsequent killings. These include changes in the emotional sphere (reduced empathy, increased cynicism), transformation of worldview attitudes (moral disintegration, a sense of chosenness), restructuring of social ties (selective isolation, seeking “like-minded” individuals), and a shift of interests toward themes of violence, death, power, and control.
After the first murder, a set of defense mechanisms are activated in the individual, aimed at resolving acute cognitive dissonance and psychologically adapting to the traumatic experience and to a new criminal identity. The most significant and frequently documented patterns in profiling practice within the analysis of post-offense behavior (adaptive mechanisms after the first murder) include the following:
— dissociation, manifesting in forms of depersonalization (a sense of alienation from one’s own “I” and actions) and derealization (perceiving the surrounding reality as unreal or surreal); research 2 confirms that dissociation is a common risk factor in violent crime.
— narcissistic overestimation of one’s own importance and grandiosity, accompanied by a distorted self-image based on a sense of chosenness, uniqueness, or superiority;
— antisocial attribution, accompanied by a negative attitude toward social norms, the law, and authority figures; such behavior is interpreted as a defensive reaction aimed at shifting blame and justifying one’s actions against a system the individual now perceives as hostile;
— behavioral strategies of suppression and avoidance: to manage escalating internal conflict and anxiety, the individual often resorts to seeking ways to suppress inner conflict and to destructive behavior patterns, including abuse of psychoactive substances (alcohol, drugs), engagement in impulsive or risky actions (thrill-seeking behavior), as well as emotional isolation as a way to avoid close interpersonal contacts that could expose the offender’s hidden identity and pose a threat to his safety.
The formation of murderous fantasies as a predictor of serial killing
Analysis of the biographies of serial offenders indicates that long before committing their first murder, many of them developed complex internal fantasies over an extended period.
Violence constituted the central element of this process. The individual experienced prolonged fixation on violent fantasy. These fantasies are not merely thoughts; they are dynamic, recurring scenarios that play a key role in shaping future criminal behavior.
A critical factor contributing to the development of such patterns, including the formation of pathological psychological mechanisms, is a dysfunctional childhood environment characterized by abuse, neglect, or other forms of psychological trauma.
In response to these chronic stressors, future serial offenders – often already displaying signs of a propensity for extreme aggression in childhood – develop complex fantasy constructs within their imagined world. These internal scenarios function as a behavioral strategy for emotional regulation, aimed at reducing anxiety and restoring a sense of control and power lost in the real world.
In these imagined scenarios, real traumatic experiences – fear, anger, hatred, and a sense of helplessness – were projected and transformed into controllable imagined images of domination, revenge, and violence. These scenes of violence were obsessively replayed in their imagination in a loop. The longer the future offender focused on them, the more brutal and often sexualized these fantasies became over time, gradually shifting from passive imagination to active, aggressive, emotionally charged scenarios of future crimes.
Early psychological trauma played a particularly significant role in this process, acting as a catalyst. It not only stimulated the development of pathological fantasies but also contributed to the weakening of internal inhibitors that restrain aggressive impulses and antisocial behavior.
The longer an individual remained immersed in such violent fantasies, the stronger the psychological dependence on them became. These fantasy scenarios began to serve the function of regulating self-esteem and strengthening the fragmented “I,” thus compensating for chronically low self-esteem.
The violent act, up to and including murder, was repeatedly “relived” in imagination via increasingly detailed and emotionally intense fantasies, which over time became more obsessive and compulsive and turned into the dominant component of the offender’s inner life.
“Murder is compensatory in the fantasy world of the murderer. Because these offenders believe they are entitled to whatever they want and that they live in an unjust world, fantasy emerges as an important escape and a place in which to express emotion and control regarding other human beings. The preference for fantasy and its centrality in the life of these men marks it as a private and powerful reality.” (Douglas, J. E., Burgess, A. W., Ressler, R. K. (1988). Sexual Homicide: Patterns and Motives). 3
Violent fantasies can arise in many people. However, for most individuals, internal and external inhibitors – psychological and social barriers – are strong enough to prevent crossing the line and to block the transition from fantasy to criminal behavior, to action. Internal inhibitors include moral principles, self-awareness, sound judgment, religious taboos, and fear of public condemnation; external inhibitors include the perceived risk of being caught, fear of punishment, or social isolation.
In a potential serial killer, these inhibitors are systematically suppressed under the influence of childhood trauma, social isolation, cognitive distortions (for example, rationalization of violence), and constant immersion in violent fantasies. As interest in the violent act intensifies and resistance to it weakens, the individual approaches the so-called “point of no return” – the moment when he commits his first murder. Criminal behavior emerges when motivational interest in it exceeds the combined strength of inhibitors (action inhibitors).
After the first victim, fantasy ceases to be purely imaginary and becomes integrated into real experience. If before the first murder fantasies focused primarily on the act of taking a life itself, after the first murder they became directed toward refining various phases of the killing – detailing and “polishing” individual stages of the crime, from selecting a victim to the method of killing and post-offense behavior. Dependence on pathological fantasies only increases over the years: they continue to substitute for genuine feelings of control and serve as an outlet for anger, as well as compensation for chronically low self-esteem and a sense of personal inadequacy.
The first murder in a series plays a critical role in the formation of a criminal signature and modus operandi. From this event onward, the offender develops a stable propensity and drive toward the violent taking of other people’s lives, often associated with antisocial personality traits, pronounced narcissism, and destructive behavior.
As noted earlier, research in behavioral criminology, forensic psychiatry, and the psychology of serial violence has shown that the latent first murder – one that goes unsolved by law enforcement – poses a particular danger. In such cases, after successfully avoiding detention, the offender often experiences a sense of power, impunity, and existential superiority.
This experience reinforces contempt for social norms and the law. Combined with the escalation of mental problems, it significantly increases the likelihood of subsequent crimes when suitable conditions and available victims arise. He learns to minimize traces, avoid mistakes from past acts, and refine his methods for concealing his behavior. Interviews with convicted offenders have shown that this process of “learning from experience” is a key factor in the evolution of their criminal behavior.
In subsequent actions, the offender typically selects locations and victims within his psychological comfort zone, where he feels most confident, in control, and relatively safe.
When circumstances align favorably for the killer and a suitable victim appears, he usually once again manifests his criminal nature. Although the first murder may be disorganized, with each subsequent act his modus operandi – the set of tactics and methods used to commit the crime – becomes increasingly deliberate, systematic, and organized, which is reflected in the refinement of behavioral strategies and improved skills for avoiding detection.
Neuropsychological research confirms that some individuals display a biological predisposition 4 to violence. This predisposition is caused by impairments in brain function, associated with low frustration tolerance (LFT) 5 (resistance to disappointment), which results from dysfunctional neural networks responsible for executive functions and emotional regulation. This may involve frontal lobe dysfunction 6, including impairments in the prefrontal cortex, which plays a key role in response inhibition, planning, and evaluation of consequences; its dysfunction leads to a reduced ability to cope with failure. These may include impairments of executive functions or emotional dysregulation — problems processing negative emotions, rapid loss of self-control, and a tendency toward aggression or depressive states, increased reactivity of the stress system, and so on. All of this manifests in behavioral reactions 7 such as outbursts of anger, impulsive actions, or protest behavior; cognitive distortions (e.g., focus on the negative), and psychological problems (chronic anxiety, depression, or psychosomatic disorders). On top of this labile brain structure, there are also stressful events and trauma related to the environment.
Analysis of the biographies of serial killers reveals a series of recurring behavioral markers that are frequently observed among them. These include pronounced narcissistic and antisocial personality traits, chronic lying, rebellious behavior, difficulties in interpersonal relationships, displays of cruelty toward animals in childhood, and others. Many offenders reported a preference for autoerotic activity and fetishistic practices, which were often integrated into their criminal scenarios.
One of the central psychological characteristics of many serial killers is a deep internal conflict between a sense of omnipotence and chronically low self-esteem – a deeply rooted sense of inadequacy. This unresolved conflict serves as a powerful motivational driver, prompting the individual to manipulate, seek power, control, and humiliate others as a temporary compensation for their own feelings of inferiority. It is this need for dominance and demonstration of control over the victim that underlies the criminal behavior of many serial killers.
As confirmed by scientific research on violent crimes, especially sexual homicides, a key idea for serial killers is the preoccupation with themes of violence and murder as a behavioral pattern. They often demonstrate an obsessive fixation on violence and murder, and a peculiar attitude toward death. John Douglas, Ann Burgess, and Robert K. Ressler write in their book “Sexual Homicide: Patterns and Motives” 3:
“In analyzing the data we obtained through interviews with the murderers, we attempted to link our quantifiable findings with indications from the murderers themselves of aggressive thoughts and fantasies directed toward sexualized death. The findings suggest that these thought patterns were established early and existed in a context of social isolation.”
“One of the indications of the presence of a fantasy is the great amount of detail provided by a subject. These details provide the best information about how the subject operates. For many of the murderers we interviewed, their detailed planning was their statement of superiority, control, and cleverness. The fantasy life usually provided a sense of power and control as well as emotional stimulation. In some instances, the fantasy appeared to protect them from becoming totally disorganized or psychotic. We discovered this, through the interviews, in the subjects’ reports of becoming enraged when victims interrupted their plans. These murderers were very sensitive to being called crazy or maniacal, for they associated these characteristics with carrying out acts that are stupid, foolish or out of control.”
The instinctive aversion to death, inherent in all people, is weakened or absent in serial killers. They are drawn to death and everything associated with it. They constantly thought about it, read literature, watched films about violence, collected “trophies,” and sometimes hinted or disclosed information to acquaintances in a veiled manner. Before the first murder, their focus was on the act of violence itself; afterward, it shifted to perfecting the murder scenario. To the offender, killing became the “highest expression of dominance” and a confirmation of control, while the boundary between fantasy and reality became blurred.
Fear of punishment (fear of legal consequences) is one of the most powerful external inhibitors for an offender. If crimes remain unsolved and the offender escapes justice, their criminal needs and the escalation of violence will only grow, and their behavior will evolve toward greater organization and control. The offender becomes more methodical, and their actions more deliberate and consistent.
Over time, the offender develops a practical understanding of law enforcement methods and begins implementing countermeasures to reduce the risk of detection. This manifests in efforts to minimize evidence, alter victim-selection tactics, and complicate crime scenarios. This “learning effect” is key to understanding why some serial killers often appear as “experts” in their field and, over time, demonstrate a high level of sophistication in their crimes.
Their confidence and professionalism are the result of a series of unpunished crimes. The primary motivation for many serial killers is not merely the act of violence but the pursuit of absolute control and power over the victim. Success and impunity serve to confirm their imagined superiority, compensating for deep-seated feelings of inadequacy.
Serial killers often begin with simpler, riskier crimes and gradually progress to more complex and controlled scenarios. The risks the offender is willing to take increase, and the structure of the killing series shows clear evolution. They devise increasingly perverse methods of killing and derive satisfaction from their own power, manipulation, and control. A serial killer does not stop voluntarily.
Serial killers and social and environmental factors shaping homicidal tendencies. Analysis of serial killers’ biographies identifies factors shaping their behavior and inclination to kill. In practice, there is no single universal profile of a serial killer, as causal factors in each case are a complex combination of psychological, socio-cultural, and biological variables. However, many studies focus on the influence of social-environmental and individual factors.
For example, a 2020 study by Abbie Jean Marono et al., “A Behaviour Sequence Analysis of Serial Killers’ 8 Lives: From Childhood Abuse to Methods of Murder,” notes that the profile of a serial killer typically includes childhood abuse and trauma linked to aggressive cognitive distortions.
In another study, “Biopsychosocial Characteristics of Children Who Later Murder: A Prospective Study” (Lewis et al., 1985) 9, authors describe the neuropsychiatric and family characteristics of nine adolescents who were clinically evaluated as adolescents and were later arrested for murder. The future murderers displayed a combination of biopsychosocial characteristics that included psychotic symptoms, major neurological impairment, a psychotic first-degree relative, violent acts during childhood, and severe physical abuse.
Another example is a 2022 study, “Youth Serial Killers: Psychological and Criminological Profiles” (García-Baamonde et al., 2022) 10, which reviews profiles of young serial killers, including common traits such as risk-seeking, lack of empathy, impulsivity, and a desire for control.
Researchers have developed many distinct concepts. Thus, for greater clarity of presentation in the format of a popular science article, we will cite the concept of the Italian school of criminology – the typology of social-environmental, individual, and relational factors (“modello SIR”), which was created based on research conducted in 2011 by Italian psychiatrists Marco De Luca and Vincenzo Mastronardi. De Luca formulated his theory after analyzing an international sample of 2,230 identified murderers.
This model views serial killer behavior as the result of interactions among innate traits, personal predispositions, social systems, and their relationships. It is also known as the systemic-relational theory for explaining serial murder.
Nicola Malizia of Università degli Studi di Enna Kore (Italy), in his work “Serial Killer: The Mechanism from Imagination to the Murder Phases” (Sociology Mind, Vol. 7, No. 2, March 17, 2017) 11, cites this SIR model (“modello SIR”):
“Serial homicidal behavior is the product of the circular combination of three factors (F) which are interwoven with each other, with variable importance from individual to individual, and of different intensities of the respective sub-factors (SF). The initials of the three factors: Social and environmental (S), Individual (I) and Relational (R) identify the SIR model, which constitutes the starting point for creating a new taxonomy of serial murder that takes into account the real complexity of the phenomenon and that can explain why a person becomes serial killer (De Luca & Mastronardi, 2011). The F factor (S) includes all social and environmental components that can affect the behavior of a serial murderer.”
1) Socio-Environmental Factor
SF1: Original family environment. In most cases, the family in which a serial killer grows up does not allow a healthy development of empathy and, consequently, the formation of a balanced personality. Physical, sexual and psychological abuse, and emotional deprivation are some of the many traumas which the subject undergoes during childhood that establish the foundations for future criminal behavior.
SF2: Insertion in society. During adolescence, and, later, as an adult, a serial murderer has, in principle, a low level of inclusion in society; in fact, very often, he does not have a rewarding job and has few friends, and is a person with few cultural interests. Even in those cases where, apparently, the subject shows a “facade of normality” (for example, is married, has children, a stable job and is considered positively by the community in which he lives), in reality it is an inclusion which stops at a superficial level and does not involve the core of the personality, haunted by deep inner anxieties.
SF3: Predisposing, facilitating and triggering events. In every life story of a serial killer, you can find predisposing, facilitating and triggering events that may occur at any time, triggering the homicidal chain reaction; these events, which for another person may seem completely harmless, instead, for a serial murderer have a disruptive emotional energy, which is able to shatter a fragile identity. The list of these events is not the same for everyone, but among the most common, there are sudden deaths, which upset the precarious internal balance of the subject, sudden abandonment by a person, easy access to a weapon, and the presence of a certain type of easily approachable victim.
SF4: Sub-cultural influences. This factor assumes considerable importance in those cases in which the serial killer grows up in a criminal environment, where, for example, the parents exhibit criminal behavior, or the subject is inserted, especially during adolescence, in a group of criminal peers who exercise a significant influence over him. Several serial killers start a criminal career early because they are included in a context that facilitates and supports the shift to an aggressive action.
SF5: Rewards and punishments by the environment. The way society reacts to the first deviant and criminal acts by a potential serial killer plays an important role in guiding the future behavior of the subject. The criminal path of an individual does not begin with a serial murder, but with less serious incidents. The subject may receive rewards or punishments for their actions, or a punishment with an educational function, which can serve to slow or block the evolution of serial homicidal behavior.
2) Individual Factor
SF1: Psychological and psychopathological traits. A serial killer has peculiar psychological characteristics that, in many cases, are related to psychopathological traits and can take different forms (mental illness, neurological deficits) and orientate his behavior. In some subjects, a “predisposition to evil” seems to exist with very early criminal behavior, even in families where there is no presence of trauma.
SF2: Sexuality. The quality and quantity of sexual impulses of the subject during the developmental period feeds their fantasy life and is a key determinant of adult behavior. The development of a perverse sexuality can be a central component of a future serial killer.
SF3: Imaginative Life (fantasies). A common feature of all serial killers is to have a very rich and varied imaginative life. Compared to the fantasies of normal individuals, those of potential serial killers are oriented early on the domain, control and destruction of other people who are imagined as “objects” at disposal for personal gratification.
SF4: Subjective needs (motivations). Throughout life, everyone has aspirations and motivations that lead them to exhibit certain behaviors. In serial killers, murder is always linked to purely personal psychological motivations; in fact, when they are captured and interrogated about what prompted them to kill, it is very difficult to understand their justification.
SF5: Processing capacity of trauma. This individual factor is very important to understand why some people become serial killers and others do not, even though there are similar life experiences in their personal history. A traumatic event (for example, the mourning of a loved one, humiliation caused by schoolmates, rejection by a sexual partner) can be handled in different ways by different people.
3) Relational Factor
SF1: Communication with himself. Serial murderers have difficulty establishing and maintaining genuinely empathic relationships with others and prefer to live in a dimension of loneliness, accompanied only by their imaginations. The quality of these fantasies and the internal dialogue that every serial killer has with himself, are of fundamental importance and influence his future action.
SF2: Communication of the individual-family of origin. The devaluing attitude of a father or a mother could irreversibly compromise the development of a child’s personality. Indeed, tensions with parents can determine future adult behavior, which can also lead them to kill women “that remind them of their mother” because, despite not having the courage to murder their own mother, they murder her symbolically by using other victims.
SF3: Communication of the individual-sexual partners. Sex is one of the fundamental aspects of human life and the type of interaction created by the individual with sexual partners has definite influence on his personality. Many of the serial killers analyzed, have developed an inadequate path composed of refusal, abandonment and humiliation of every kind. Therefore, they come to hate a certain category of people (in most cases, women) against whom they wish to take revenge by killing them.
SF4: Communication of the individual-society. Some serial killers manage to camouflage themselves behind a mask of normality by opening very superficial relationships with other social subjects, but, in fact, continue to treat people as mere “objects” and do not believe that it is possible to establish a positive relationship. In the event that serial murderers have their own family (maybe married with children), the relationship with the family has the same trend as the external ones: a “facade of normality”, while, in reality, domestic life is marked by a daily underlying tension.
SF5: Ways of learning violence. From what we can deduce, a human being is not born a serial killer, but, over years, learns the use of violence to satisfy his needs (identity, sexual, personal gratification, omnipotence) and ways of learning are always a question of interaction with one or more negative patterns taken as reference points.”
In the book “Journey Into Darkness,” John Douglas and Mark Olshaker 12 write: “Like many offenders, this one would likely display changes of behavior after the first killings which would be noticeable to those around him. These could include heavier reliance on alcohol or drugs, change in sleeping or eating habits, weight loss, anxiety, more eagerness to associate with others. He would also closely follow the news of the investigation. We told the police that the public could be extremely instrumental in identifying the killer if these traits were publicized and it was made clear that there would be at least one person close enough to him to have a sense of what he’d done.”
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Source:
1. Douglas, J. E., Burgess, A. W., Burgess, A. G., & Ressler, R. K. (2013). Crime Classification Manual: A Standard System for Investigating and Classifying Violent Crimes.
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5. Best, M., Williams, J. M., & Coccaro, E. F. (2002). Evidence for a dysfunctional prefrontal circuit in patients with an impulsive aggressive disorder. Proceedings of the National Academy of Sciences of the United States of America, 99(12), 8448–8453. https://pmc.ncbi.nlm.nih.gov/articles/PMC123087/#:~:text=Clues%20to%20the%20neurobiology%20of,OMPCC
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7. Siep, N. et al. (2019). Anger provocation increases limbic and decreases medial prefrontal cortex connectivity with the left amygdala in reactive aggressive violent offenders. Brain imaging and behavior, 13(5), 1311–1323. https://pmc.ncbi.nlm.nih.gov/articles/PMC6732149/#:~:text=task,In%20addition%2C%20an
8. Abbie Jean Marono et al., “A Behaviour Sequence Analysis of Serial Killers’ Lives: From Childhood Abuse to Methods of Murder”. https://pmc.ncbi.nlm.nih.gov/articles/PMC7144278/#:~:text=Research%20has%20suggested%20that%20the,Pettit%2C%20Bates%2C%20%26%20Valente%2C%201995
9. “Biopsychosocial Characteristics of Children Who Later Murder: A Prospective Study” (Lewis et al., 1985). https://pmc.ncbi.nlm.nih.gov/articles/PMC2072934/#:~:text=The%20authors%20document%20the%20childhood,of%20violence%20and%20discuss%20ethical
10.“Youth Serial Killers: Psychological and Criminological Profiles” (García-Baamonde et al., 2022). https://pmc.ncbi.nlm.nih.gov/articles/PMC9105323/#:~:text=In%20short%2C%20what%20we%20can,49
11. Nicola Malizia “Serial Killer: The Mechanism from Imagination to the Murder Phases” (Sociology Mind, Vol. 7, No. 2, March 17, 2017), cites this SIR model (“modello SIR”). https://www.scirp.org/journal/paperinformation?paperid=74772#ref10
12. John Douglas and Mark Olshaker, “Journey Into Darkness”
