The criminal act known as MURDER is defined in a number of ways, but in most references the definition is distilled to the following words: an unlawful killing with malice. The words unlawful and malice give the term its defining structure and distinguishes the act from acceptable killings, such as in times of war or other justifiable homicides.

In researching the law related to killings, a murder can be defined by three basic characteristics and those must be proven beyond a reasonable doubt: 1) the act of causing a death must be deliberate, meaning it must be premeditated and calculated; 2) the act must be intentional to either kill, cause grievous bodily harm or be one of reckless indifference to human life; and 3) the act must not have been carried out as self-defense.

But beyond those specific legal references, I’ve been thinking about what really defines a murder. Initially, I came across a reference to a 1968 TV movie called Prescription For Murder. It was about a psychiatrist who had an affair with a patient and convinced her to help him kill his wife (a deliberate, intentional, non-self-defense killing). A little known, persistent detective named Columbo, played by Peter Falk, solved the case and this led to his highly successful 1970’s TV series Columbo.

Detective Columbo was a favorite of mine, not only because he solved his cases, but also because he solved them with a psychological twist. He looked beyond the obvious and studied the motivational possibilities behind the killing.

So I asked myself the same questions I suspect the writers on the Columbo series had to ask before writing every episode: “Why do people kill?” and “Why choose to kill rather than seek other, less consequential ways to solve a problem?”

Well, it turns out that science has the answers. It seems that the rationalizations for murder are much more complex than simply motive, method and opportunity.

Current science tells us there are three main reasons why people choose to kill over other, less violent methods of resolving a major issue in their lives.

One is genetics. People who turn to killing are thought to be naturally more aggressive and it’s often because they inherit one or more specific genes for violence. These so-called warrior genes are specifically tied to a predisposition to violence and aggression.

Another involves a brain malfunction. For instance, a loss of brain functionality in, or a failure to properly develop, the frontal lobe can lead to violence and murder. The frontal lobe (that part of the brain under our foreheads and behind our eyes) contains the coding for ethics and morality. It’s also the center for impulse control. So any frontal lobe damage or misdirected development can lead to miscues of ethics and moral decision-making, causing improper responses to life’s everyday challenges.

The third reason people turn to lethal violence is abuse. This can be sexual, psychological or physical in nature. Abuse during the childhood years are the most damaging and can lead to psychopathologies later in life. The specific type of abuse, along with the intensity and duration of the abuse, often determines the specific psychopathology that may result.

As one can expect, specific tendencies to MURDER may develop as a result of a combination of these factors. A violent genetic predisposition may play a greater role when a child is abused and yet be inconsequential if the child is the product of a stable, caring family environment. A child with frontal lobe abnormalities may be channeled into a productive life if taught to control improper impulses, but spin out of control in an abusive environment. The combinations are endless, and so are the resulting pathologies and potential murders that can result.

There is no “one size fits all” when it comes to the urge to kill. The motivations and underlying pathologies are as numerous as its methods, but there is one common factor in almost every murder–the killer feels strongly justified, no matter how malicious the act.

Thoughts? Comments? I’d love to hear them!