Why do people kill?
A Typology of Violent Offenders

At various times, I have been asked to lecture on the topic: why do people kill? Why do they commit murder? How do we explain acts of violence. The following is not an exhaustive explanation. It's a handout I use when I speak about different types of killers and the motivations for different crimes. But it describes many, if not most types of homicide and most acts of violence. It describes most of the killers and most of the violent individuals I have interviewed.

Chronically Aggressive Individuals

  • Easily frustrated, limited or poor impulse control
  • Frequently express anger or hostility
  • Resents authority, defiant with supervisors.
  • May express hostility through “passive-aggressive” behavior
  • Believes violence and/or aggression are legitimate responses to various interpersonal problems in life (i.e., if someone provokes you, you fight back)
  • Although they might never admit it, pleasure or reinforcement is derived from the expression of anger (i.e., it feels good to blow someone off; it makes you feel alive; it gives you a sense of power)
  • Often display the characteristics of a “stimulus seeker” - they engage in bold, fearless, or reckless behavior and are prone towards substance abuse
  • Most typically, violence occurs in a situational context: an offense, fight, or disagreement
  • Sometimes just get carried away in a particular situation (domestic violence, child battering)
  • Less likely to engage in acts of unexpected “explosive” violence
The Over-Controlled Hostility Type
  • Rarely display or express anger - they don’t cuss or yell, and may be offended by such
  • Emotionally rigid and inflexible: appear to be polite, serious, and sober, rarely “loose” or jocular
  • Cognitively rigid and inflexible: very strict about interpreting rules; usually go for the letter, rather than the spirit of the law
  • Morally righteous and upstanding: see themselves as “good people”
  • Often judgmental: see others as “not such good people”
  • Non-assertive or passive; their passivity causes others to take advantage of them
  • Anger builds up like in a pressure cooker, before they explode
  • After the violence, people say that they never expected it, “he always seemed like such a nice guy; he was always so quiet”
The Hurt and Resentful
  • Feel that people walk on them and that they are never treated fairly
  • When they are passed over, there is always someone else to blame
  • Things are easier for everyone else: other people get more and have more advantages.
  • They do not accept criticism well
  • In response to reprimands, they develop grudges, which are sometimes deeply held
  • They are often whiners and complainers, as a matter of attitude
  • They wallow in their victimization and are psychologically impotent
  • Violence occurs because they hold grudges and are “impotent” to deal with their anger in other ways
The Traumatized
  • Aggression occurs in response to a single, massive assault on their identity
  • Something happens that is potently offensive, absolutely intolerable, and which strips them of all sense of personal power
  • The essence of their existence (or their manhood) will be destroyed if they do not respond
  • Violence is predictable & preventable
The Obsessive
  • Immature and narcissistic individuals who demand or crave attention and affection
  • Absolutely cannot stand to be deprived of desired gratifications, like a baby who cries because mother removes the breast
  • When deprived of love, they continue crying: repeated phone calls, following the object of their obsession, etc.
  • As frustration continues, they escalate: “dead flowers”, punctured tires, suicide gestures
  • Violence because: “if I can’t have her, nobody can.” ... or: “if she won’t have me, she won’t have anything.”
The Paranoid
  • Jealous Type: Delusionally believes their lover is unfaithful
  • Persecuted Type: Delusionally believes that people are out to get him
  • Typically engage in behaviors which make their paranoid beliefs come true
  • Delusions may reach the point at which the person is grossly out of contact with reality (may be insane).
The Insane
  • Rare: does not understand the nature and quality of their actions.
  • More typical: fundamental misperceptions of reality, incapable of rational behavior, delusional beliefs deprive them of the ability to know that their behavior is wrong, beliefs and perceptions are incongruent with reality.
  • Twisted, psychotic beliefs about what is right, what is wrong, and what is necessary.
The Just Plain Bad & Angry
  • A combination of most of the above (except for insane): angry, hostile, jealous, resentful, impotent, and disturbed individuals, who are socially isolated, socially inadequate, and who feel worthless
  • May be seeking attention
  • May be seeking revenge

Copyright, Paul G. Mattiuzzi, Ph.D.