How Not to Raise a "Monster"

The Forensic Psychology of Parenting and Dark Personality Traits

Tommy Lynn Sells was seven years old when his mother let a neighborhood man take him on day trips, shower him with gifts, and eventually sleep at his house. The man was a pedophile who molested Tommy for years. When Tommy’s mother found out, she continued to allow the relationship.

Serial killer Tommy Lee Sells was executed in Texas in 2014 for the murder of a thirteen-year girl. He claimed to have over seventy victims.

By thirteen, she’d abandoned him entirely. She packed up her other children and left town without a forwarding address. Tommy came home to an empty house. He spent the next two decades drifting across America, killing an estimated twenty-two people in more than a dozen states.

Henry Lee Lucas’s mother Viola was a sex worker who forced her son to watch her with clients, then beat him when he tried to look away. She dressed him as a girl with curled hair and sent him to school to be humiliated by his classmates. She killed every pet he tried to keep. When a teacher bought him shoes because he had none, Viola beat him for accepting charity. She once struck him with a wooden board so hard he fell into a coma for three days.

Henry Lee Lucas, convicted of killing his mother in 1960 and two other women in 1983.

At twenty-three, Lucas stabbed her to death. He spent the rest of his life killing women who reminded him of her.

Dellen Millard was Canada’s youngest pilot at fourteen, wealthy, charming, and adored by his mother, who once compared presenting her newborn son to the world to Mufasa holding up Simba in The Lion King. He grew up believing he was destined for greatness. When legitimate success didn’t satisfy him, he turned to theft for the thrill. When theft lost its luster, he moved to murder, killing his own father, a former girlfriend, and a stranger, all within a year.

Convicted triple murderer whose victims include his father, his girlfriend, and a man he tricked into taking a ride in his vehicle.

Three childhoods. Three trajectories. Three killers. The common thread isn’t poverty or broken homes or genetic destiny. It’s what happened, or didn’t happen, between parent and child, sustained over years.

The people we wind up calling “monsters” because of their horrendous deeds aren’t born; they’re often molded. And while we can’t blame every violent offender’s parents for their crimes, decades of research tells us something forensically significant: parenting styles and parental personality traits play a meaningful role in the development of the Dark Tetrad traits (narcissism, psychopathy, Machiavellianism, and sadism) that underpin so much of the violence we investigate.

A Word Before We Go Further

If you’ve ever been too exhausted to respond to your kid’s twentieth complaint of the day, you haven’t created a psychopath. If you’ve told your daughter she’s the smartest kid in her class, you haven’t manufactured a narcissist. If you’ve snapped “because I said so” after the fifteenth “why,” you haven’t set your son on the path to Machiavellianism.

Parenting is relentless, often thankless work. Anyone who’s raised children knows the gap between the parent you planned to be and the parent you are at 2 AM with a sick toddler or facing down a defiant teenager. The research we’re about to discuss identifies risk factors, not destiny. We’re talking about sustained patterns over years, not bad days or rough patches.

Our children don’t need us to be perfect. They just need parents who are present enough, warm enough, boundaried enough. The developmental system has slack built in. Kids are more resilient than we sometimes give them credit for, and the occasional parenting misstep is part of normal family life.

What the research shows, and what the cases above illustrate, is what happens when the pattern becomes chronic, severe, and unrelenting. When a child’s existence is treated as an inconvenience over months and years. When emotional absence isn’t a bad week but a way of life. When overvaluation isn’t occasional pride but a sustained campaign to convince a child they’re superior to everyone around them.

Context matters. Severity matters. Chronicity matters.

With that in mind, let’s look at what the science tells us.

The Dark Tetrad: Beyond the Triad

First coined by psychologists Delroy Paulhus and Kevin Williams in 2002, the Dark Triad originally encompassed narcissism, psychopathy, and Machiavellianism. But in 2013, researchers Erin Buckels, Daniel Jones, and Paulhus proposed an expansion: the Dark Tetrad, adding everyday sadism as a fourth distinct trait. It captured something the original three missed.

Narcissism manifests as a grandiose self-view, entitlement, and a stunning lack of empathy. Narcissists crave admiration the way the rest of us crave oxygen. The vulnerable subtype adds fragility and deep resentment when that admiration doesn’t materialize.

Psychopathy features callousness, impulsivity, and superficial charm. Primary psychopathy, the “born” type, involves fearlessness and emotional detachment. Secondary psychopathy often emerges from trauma and manifests as reactive aggression. Critically, psychopaths are indifferent to others’ suffering. They don’t care, but they don’t particularly enjoy it either.

Machiavellianism is all about cunning manipulation and cynicism. These folks see other humans as pawns to be moved around for personal gain, and they feel zero remorse about it.

Sadism is the distinguishing addition. While psychopaths are indifferent to suffering and Machiavellians use cruelty instrumentally when useful, sadists enjoy causing pain. They derive pleasure from hurting others and will go out of their way, “pay extra” as researchers put it, to inflict suffering even when it serves no strategic purpose.

This distinction matters enormously in forensic work. The offender who kills efficiently to eliminate a witness (psychopathy, Machiavellianism) is different from the one who prolongs suffering, takes trophies, or returns to the scene to relive the experience (sadism). The torture-murderers, the ones who overkill, the ones who seem to savor the act: sadism is often the distinguishing feature.

Meta-analytic research shows sadism correlates most strongly with psychopathy (r = 0.58), then Machiavellianism (0.43), then narcissism (0.26). But it contributes unique variance in predicting cruel behavior. Studies demonstrate that only individuals with sadistic traits derive actual pleasure from acts of cruelty, a finding that distinguishes sadism as genuinely distinct from mere callousness.

These traits aren’t binary switches. They exist on a spectrum, and many offenders show elevations across multiple dimensions. High levels predict everything from workplace sabotage to violent crime. And while genetics play a substantial role (heritability estimates hover around 40-60%), environment tips the scales.

But here’s what makes this complicated: the relationship between parenting and child outcomes runs in both directions.

Kids Aren’t Blank Slates

Before we examine how parenting shapes Dark Tetrad traits, we need to acknowledge an uncomfortable truth: children shape parenting too.

A child born with early callous-unemotional traits, reduced empathy, blunted emotional responses, may elicit different parenting than a highly sensitive, emotionally expressive sibling. Parents might become harsher with a child who doesn’t respond to normal discipline, or more distant from a child who doesn’t seem to need connection. This can create a feedback loop where the child’s temperament pulls for exactly the parenting style that makes things worse.

Research on this bidirectional effect is robust. Longitudinal studies show that children’s difficult behaviors predict increases in harsh parenting over time, just as harsh parenting predicts increases in difficult behaviors. It’s a dance, not a one-way transmission.

Some children are highly sensitive to their environment for better or worse. Good parenting helps them flourish spectacularly; poor parenting hits them especially hard. Others are remarkably resilient regardless of conditions. Same family, same parenting, different outcomes.

Consider Jeffrey Dahmer’s brother David, raised in the same household with the same emotionally absent parents. David grew up to be a well-adjusted professional who changed his name and lived a quiet, law-abiding life. Same family, radically different trajectory. We don’t fully understand why some children are devastated by neglect while others survive it, but it reminds us that parenting is a risk factor, not a guarantee.

This doesn’t let parents off the hook. It means the picture is more complex than “bad parenting creates bad kids.” Some parent-child combinations are simply harder. Some children require more than their parents have to give. And some parents, facing a difficult child, rise to the challenge while others retreat into the patterns that make things worse.

The Parenting Pathways to Darkness

With those caveats in mind, Diana Baumrind’s classic parenting framework (authoritative, authoritarian, permissive, and neglectful) helps map how different styles, when chronic and severe, can contribute to different Dark Tetrad traits.

Neglectful Parenting: The Psychopathy Pathway

Low warmth, low control, emotional absence. When sustained over years, this pattern is most consistently linked to psychopathy.

Tommy Lynn Sells embodies this trajectory. His mother Nina sent him to live with an aunt shortly after his twin sister died of meningitis when they were toddlers. The aunt wanted to adopt him; Nina refused, then promptly ignored him. Diane Fanning, who wrote the definitive book on Sells, noted that he became a chronic truant by age seven, “an indication of his mother’s indifference.” Nina allowed a known pedophile named Willis Clark to groom and molest her son for years. She let him drink alcohol at seven. And when he became too difficult at thirteen, she simply left. She took her other children and vanished without telling him where they’d gone.

What emerged was a drifter with no attachments, no empathy, no roots. Sells hitchhiked and hopped freight trains across America for two decades, killing without pattern or apparent emotion: children, women, families, strangers. He told interviewers the thrill of killing was “like a drug” and aspired to become “the worst serial killer of all time.” When asked about remorse, he had none to report.

Research consistently shows that perceived parental rejection and emotional coldness predict elevated psychopathic traits. A 2022 German study of over 1,300 adolescents found that parental rejection by both parents, combined with harsh punishment, was positively associated with psychopathy, Machiavellianism, and narcissism. Critically, maternal emotional warmth was negatively associated with psychopathy. Warmth from mom specifically served as a protective factor.

Nina Sells offered no warmth, no protection, no presence. Her son became what that absence created: someone who felt nothing for anyone, including himself.

Psychological Aggression: The Sadism Pathway

A 2025 study by Galán and colleagues examining childhood abuse and Dark Tetrad traits found something striking: psychological aggression from parents uniquely and positively predicted both psychopathy and sadism. This wasn’t about physical abuse. It was about chronic verbal cruelty, humiliation, belittling, and emotional terrorism.

Henry Lee Lucas’s childhood reads like a manual for manufacturing a sadist. His mother Viola didn’t just neglect him; she systematically degraded him. She forced him to watch her have sex with clients. When he tried to walk away, she beat him. She dressed him as a girl with curled hair and sent him to school to be mocked by classmates. A half-sister later confirmed she had photographs. Viola killed any animal he tried to keep as a pet, including a mule given to him by an uncle. When a teacher, taking pity on the barefoot boy, bought him shoes, Viola beat him for “accepting charity.” She once struck him with a wooden board so hard he fell into a coma for three days.

Psychologists who later evaluated Lucas concluded that his violent misogyny stemmed directly from his hatred of his mother, hatred born from sustained humiliation. Lucas himself said he was treated “like the dog of the family,” made to do “things that no human being would want to do.” Viola never allowed him to express emotion; he wasn’t even permitted to cry at his father’s funeral.

This makes developmental sense. Children subjected to sustained psychological cruelty learn that inflicting emotional pain is normal, perhaps even satisfying. They may identify with the aggressor, internalizing the lesson that power comes from making others suffer. The pleasure component that distinguishes sadism from mere callousness may emerge when causing pain becomes associated with feeling in control, reversing the helplessness of being victimized.

At twenty-three, Lucas stabbed Viola to death. He went on to kill at least ten more women, targeting victims who reminded him of his mother. The sustained psychological aggression he endured didn’t just produce callousness. It produced pleasure in cruelty directed specifically at women.

Overindulgent Parenting: The Narcissism Pathway

A 2015 study published in PNAS followed 565 Dutch children aged 7-12 and found something that challenged old assumptions: narcissism wasn’t predicted by cold, unloving parents (the classic psychoanalytic view). Instead, it was predicted by parental overvaluation, treating kids as more special or entitled than others.

Children whose parents consistently described them as exceptional developed inflated, fragile self-views. They believed themselves superior but constantly craved validation. Meanwhile, genuine warmth (affection, appreciation, love without the pedestal) fostered healthy self-esteem, not narcissism.

Dellen Millard’s trajectory illustrates this pathway. As a forensic psychologist who analyzed the case, I noted that Millard’s mother Madeline Burns once compared his birth to Mufasa holding up Simba, the new lion king, “for the world to admire.” This wasn’t casual parental pride; it was a worldview. Dellen attended private schools, took lavish vacations, dabbled in expensive hobbies. He became Canada’s youngest person to pilot both a helicopter and airplane solo on the same day, on his fourteenth birthday. But as he grew older, nothing satisfied him. The ordinary achievements that gratify most people felt beneath him.

He sought increasingly extreme thrills: off-road racing, skydiving, jumping off roofs at parties. When legitimate excitement wasn’t enough, he turned to theft, finding his “real passion” in planning and executing heists. He collected followers rather than friends, people he could control through charm or money. When theft lost its luster, he moved to murder.

Even after two first-degree murder convictions, his mother wrote a letter describing her son in terms that bore little resemblance to reality, still apparently unable to see him as anything other than the special child she’d raised him to believe he was. Millard was originally sentenced to serve 75 years before parole eligibility, the first murderer in Ontario to receive such a sentence, though a 2022 Supreme Court ruling later struck down consecutive parole periods as unconstitutional.

The key word in the research is consistently. Telling your kid she did a great job on her school play doesn’t create a narcissist. Systematically teaching her that she’s more talented, more deserving, and more special than other children, while shielding her from any experience that might challenge that belief: that’s the pattern associated with narcissistic development.

The Machiavellianism Overlap

Machiavellianism, the strategic, cynical manipulation of others for personal gain, shares significant developmental roots with psychopathy. Both emerge from cold, rejecting, neglectful parenting environments. The meta-analytic correlation between the two traits is .66: substantial overlap, but not identical.

What distinguishes Machiavellianism developmentally? Research by Láng and Abell (2018) identified one particularly relevant factor: exposure to intense, unresolved parental conflict. Children who witness their parents locked in chronic warfare, manipulating each other, betraying trust, treating the relationship as a battlefield, learn that this is how human connection works. Trust is seen as foolish. Relationships become transactional. The cynical worldview that defines Machiavellianism gets modeled in the home before it’s ever applied outside it.

Interestingly, research suggests Machiavellianism may be the Dark Tetrad trait most influenced by environmental factors, particularly variations in parental care and attachment security. The strategic, calculating quality that distinguishes it from impulsive psychopathy may require extra learning, more observation of how manipulation works in practice.

When Parents’ Deny the Obvious

Sometimes the parenting failure isn’t what parents do to children. It’s what they refuse to see.

Herb Baumeister’s teachers flagged bizarre behavior when he was in high school: he placed a dead crow on a teacher’s desk, urinated on another teacher’s desk, expressed curiosity about the taste of human urine, and showed an unusual interest in dead animals. His father took him to a psychiatrist, who diagnosed paranoid schizophrenia and antisocial personality disorder.

Herb Baumeister is believed to killed at least twenty-five victims between the late 1980s and early 1990s.

And that was the end of it. Nothing happened. No follow-through, no monitoring, no treatment. The evaluation went into a file somewhere, and life continued on.

Parental denial operates as its own risk factor. When parents refuse to acknowledge their child’s capacity for concerning behavior, when they explain away every red flag, blame every teacher or peer who raises concerns, treat professional diagnoses as attacks rather than information, they eliminate the possibility of early intervention. The child learns that their behavior has no real consequences, that someone will always smooth things over, that the rules don’t apply to them.

This isn’t the same as supporting your child through difficulties. It’s the refusal to see difficulties as real, a protective fantasy that leaves the child unprotected from their own trajectory.

Years later, when Baumeister’s teenage son found a human skull on their property, the initial responses were again nonchalent. Baumeister’s wife accepted Herb’s explanation that it came from his father’s medical skeleton, who had been an anesthesiologist. You’d think she might have questioned why a medical skeleton would be buried in their yard. Nope.

But Julie Baumeister was not in denial; she had been in shock. Despite initially believing him, Julie became increasingly fearful and concerned about Herb’s erratic behavior and mood swings over the following 18 months. Two years later, in the middle of divorce proceedings and having learned that husband was a suspect in the disappearances of several men, Julie granted police permission to search the property. It was June 1996.

Severe Physical Abuse: Multiple Pathways

The 2025 Galán study found that severe assault during childhood predicted elevations in Machiavellianism, narcissism, and psychopathy, essentially loading the dice across multiple traits. Interestingly, ordinary corporal punishment (spanking) didn’t show these associations; it was the severe end, the beatings, injuries, and violence that crossed into abuse, that predicted dark trait development.

This suggests a threshold effect: garden-variety imperfect discipline doesn’t create monsters, but severe physical abuse can push development in multiple dark directions simultaneously.

Protective Factors: What Keeps Kids Safe

Here’s the hopeful part: parenting isn’t the only influence on development, and many children with objectively terrible home lives don’t develop Dark Tetrad traits.

One caring adult. Research consistently shows that a single stable, supportive relationship with an adult, whether a grandparent, teacher, coach, or neighbor, can buffer children against even severe family dysfunction. This person doesn’t have to be perfect or constantly available. They just have to be reliably present and genuinely caring.

Peer relationships. Positive friendships provide emotional support, model healthy relationships, and create a sense of belonging outside the family. Isolation is a risk factor; connection is protective.

School and community engagement. Structured activities, achievement opportunities, and feeling valued in a community context all contribute to resilience. Kids who have something to be good at and somewhere to belong have resources to draw on.

Temperament. Some children are simply more resilient by nature. This isn’t fair, it’s not their accomplishment and not something struggling children can just decide to have, but it’s real. The dandelion children who survive despite terrible circumstances aren’t evidence that parenting doesn’t matter; they’re evidence that human development is complex.

Tommy Lynn Sells had no caring adults. Henry Lee Lucas had no positive peer relationships; he dropped out of school and drifted alone. Dellen Millard had followers, not friends, relationships based on what he could provide rather than genuine connection. The protective factors were absent across the board.

When multiple systems fail simultaneously (absent parents, no outside relationships, no community ties, no intervention despite warning signs), the risk compounds.

The Intergenerational Transmission Problem

Parents with Dark Tetrad traits often unwittingly breed them in their children, but this too is probabilistic, not deterministic.

Research shows maternal psychopathy links to child callous-unemotional traits via harsh parenting practices. A parent high in Machiavellianism sees relationships as transactional and may teach children the same. A narcissistic parent may overvalue their child as an extension of themselves, not as a separate person deserving authentic connection. A psychopathic parent may lack the emotional attunement to notice their child’s distress. And a sadistic parent may model that cruelty is acceptable, even pleasurable.

But many children of Dark Tetrad parents don’t develop these traits themselves. Some actively reject their parents’ patterns. Some find other models. Some, through temperament or outside relationships, develop differently despite their home environment.

That’s what makes David Dahmer so significant as a counterpoint. Raised in the same household as Jeffrey, same emotionally absent mother battling depression, same frequently absent father, David became a well-adjusted adult who changed his name and built a quiet, normal life. The parenting was the same. The outcome wasn’t.

Understanding why requires acknowledging what we don’t know. Temperament differences, birth order effects, subtle variations in how each child experienced the same household, random developmental events: all of these contribute. The honest answer is that development is probabilistic. Parenting loads the dice but doesn’t determine every roll.

Early Warning Signs: What We Look For

Can you spot Dark Tetrad traits developing in children? Psychologists caution against formal diagnosis before adolescence, when personalities consolidate. But warning signs can appear earlier:

Narcissism indicators: Extreme sensitivity to criticism combined with grandiose self-presentation. Constant need to be center of attention with distress when attention goes elsewhere. Difficulty acknowledging mistakes or accepting responsibility.

Psychopathy indicators: Callous disregard for others’ feelings that persists across contexts. Shallow emotional responses, particularly to others’ distress. Chronic lying without apparent guilt. Impulsivity combined with lack of remorse.

Machiavellianism indicators: Manipulative behavior that seems calculated rather than impulsive. Cynical view of others’ motives. Strategic relationship behavior, befriending people for what they can provide.

Sadism indicators: Enjoyment of others’ pain is the key distinguishing feature. Animal cruelty, particularly when the child seems to derive pleasure rather than acting impulsively. Bullying behavior that seems motivated by enjoyment rather than social dominance. Interest in violent content that goes beyond typical curiosity. Fascination with torture, suffering, or degradation.

The key is pattern recognition. A single incident is a data point. Persistent patterns across time and contexts are concerning.

Herb Baumeister’s teachers saw the pattern: the dead crow, the urination, the morbid curiosity. They flagged it. A psychiatrist diagnosed it. Then the system failed to follow through. Each warning sign was a signal that, if heeded, might have changed the trajectory.

What the Research Suggests

The evidence points toward some general principles, though every family is different and these aren’t commandments from on high.

Warmth matters. Genuine affection, expressed freely and consistently, is associated with healthy self-esteem and lower Dark Tetrad traits. This doesn’t mean constant praise. It means your kid knows you love them even when they mess up.

So do boundaries. Kids need structure and limits. The absence of boundaries is associated with narcissistic development; harsh and arbitrary boundaries are associated with Machiavellianism and psychopathy. The sweet spot is firm, consistent, and explained.

Effort-based feedback tends to work better than trait-based feedback. “You worked hard on that” builds resilience better than “you’re so smart.” But occasional trait praise isn’t going to ruin your child.

Letting kids experience manageable frustration builds tolerance. You can’t smooth every bump, and you shouldn’t try. But this doesn’t mean abandoning them to struggle. It means being present while they work through age-appropriate challenges.

Paying attention to distress matters. When a child expresses fear, sadness, or confusion, taking it seriously, even if you can’t fix it, communicates that their inner life matters. Chronic dismissal communicates that it doesn’t.

Psychological aggression is not a parenting tool. Belittling, humiliating, and verbally terrorizing children doesn’t toughen them up. It predicts both psychopathy and sadism. There’s a difference between firm discipline and cruelty.

Your own mental health affects your parenting. Parents dealing with their own depression, personality issues, or life stress have fewer resources for their kids. Getting help for yourself is also getting help for them.

Animal cruelty is always a red flag. If your child is hurting animals, especially if they seem to enjoy it, this warrants immediate professional evaluation. Don’t dismiss it as “boys being boys” or a phase.

None of this is rocket science, and most parents are already doing most of it most of the time. The problems emerge when these elements are chronically absent or distorted, when dismissal becomes the default, when boundaries are either nonexistent or brutal, when the parent’s needs consistently override the child’s.

And when you’re having a rough patch, because everyone does, the research suggests it’s not the end of the world. Kids can handle imperfect parenting. What they can’t handle is sustained absence, sustained cruelty, or sustained overvaluation with no reality checks.

The Forensic Takeaway

Pulling this research together reveals something significant for those of us who work with violent offenders: the Dark Tetrad isn’t a single pathway but a spectrum of imbalances, emerging from the interaction of temperament, sustained environmental patterns, and the presence or absence of protective factors.

Chronic emotional absence and rejection is most consistently linked to psychopathy.

Chronic psychological aggression and cruelty predicts both psychopathy and sadism. The enjoyment of others’ suffering may emerge from identifying with an aggressor or from associating the infliction of pain with power and control.

Chronic overvaluation without boundaries is most consistently linked to narcissism.

Chronic exposure to interparental conflict and manipulation is linked to Machiavellianism.

Severe physical abuse loads the dice across multiple traits.

The cases we’ve examined show what happens when these failure patterns converge with no protective factors to buffer them:

Tommy Lynn Sells experienced pure neglect: a mother who let him be abused, then abandoned him entirely. The result was a drifter with no attachments who killed without apparent emotion across two decades.

Henry Lee Lucas experienced sustained psychological torture: humiliation, degradation, cruelty designed to destroy his sense of self. The result was a killer who targeted women resembling his mother, whose violence had a sadistic quality rooted in his relationship with the woman who tormented him.

Dellen Millard experienced overvaluation without limits, the specialness narrative with no reality checks. The result was a grandiose adult who sought ever-escalating thrills because nothing felt worthy of his inflated self-concept, ultimately including murder.

Herb Baumeister’s warning signs were seen, diagnosed, and then ignored. The result was a serial killer whose trajectory might have been interrupted if his parents had followed through on what they already knew.

Each developmental pathway produced a different kind of violence. Understanding those pathways helps us assess risk, plan interventions, and recognize patterns in the cases we investigate.

Here’s the forensic takeaway: when parenting extremes are chronic and severe, and when protective factors are absent, the risk of Dark Tetrad development increases substantially. Genetics load the gun, environment influences whether and how it’s fired, and protective factors can interrupt the process at multiple points.

This reframes our understanding. The “born evil” myth crumbles under the evidence, but so does the “parents are everything” myth. Human development is a complex system with multiple inputs. Our job is to understand how those inputs interacted in a particular case, not to assign simple blame.

Because every monster was once a child. And while we can’t save them all, understanding what went wrong might help us save some.

References

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Bonfá-Araujo, B., et al. (2022). “Considering sadism in the shadow of the Dark Triad traits: A meta-analytic review of the Dark Tetrad.” Personality and Individual Differences, 197.

Fanning, D. (2003). Through the Window: The Terrifying True Story of Cross-Country Killer Tommy Lynn Sells. New York: St. Martin’s Press.

Ferencz, T., et al. (2022). “Sibling relationship quality and parental rearing style influence the development of Dark Triad traits.” Current Psychology.

Galán, M., Pineda, D., Rico-Bordera, P., Piqueras, J.A., & Muris, P. (2025). “Dark childhood, dark personality: Relations between experiences of child abuse and dark tetrad traits.” Personality and Individual Differences.

Johnston, J. (2019). “The Case of Serial Killer Dellen Millard: Indulgent parents, narcissistic children, and too much of a good thing.” Psychology Today.

Láng, A. & Abell, L. (2018). “Relationship between interparental functioning and adolescents’ level of Machiavellianism: A multi-perspective approach.” Personality and Individual Differences, 120, 213-221.

Mitchell, H. & Aamodt, M.G. (2005). “The incidence of child abuse in serial killers.” Journal of Police and Criminal Psychology, 20(1), 40-47.

Paulhus, D.L. & Williams, K.M. (2002). “The Dark Triad of personality: Narcissism, Machiavellianism and psychopathy.” Journal of Research in Personality, 36(6), 556-563.

PLoS One (2022). “What makes a violent mind? The interplay of parental rearing, dark triad personality traits and propensity for violence in a sample of German adolescents.”

Radford University Serial Killer Database. Serial killer case files for Tommy Lynn Sells, Henry Lee Lucas, and Herb Baumeister.

Weinstein, F. & Wilson, M. (1998). Where the Bodies Are Buried. New York: St. Martin’s Press.

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