The adage, write what you know, is true up to a point. You don’t have to be a serial killer to write about one. Unless of course you know a real serial killer, then you can just ask him.
We cannot understand the irrational. We can only observe it. So, how can a writer attempt to get into their head when their brains have been encoded improperly? The serial killer’s that is, not the writer’s.
While you’re in there, you’re going to see disturbing things that can be the stuff of nightmares; human nature at its worst. The usual behavioral traits we have all experienced, the stuff we write about in most novels are not applicable here.
The most broadly recognized mental disorder associated with serial killers is the Antisocial Personality Disorder, classified as a cluster B personality in the DSM-IV, closely related to psychopathy. Neuroscience considers psychopathy to be a developmental disorder rather than a clinical diagnosis. Because their brains have not been encoded properly during development, serial killers may exhibit a reduced area of prefrontal grey matter, an abnormal Amygdala, and an asymmetric hippocampi. When you understand how these areas of the brain affect behavior, and when there is abnormal encoding, you find the typical behavioral traits found in serial killers. These would include a total lack of empathy, a sense of grandiosity, manipulation, charm, narcissism and intimidation. These are the traits you can use in your novel to develop your character's personality. The FBI recognizes all of these personality traits as definitive for a serial killer. There are other personality disorders that can overlap with APD, but a serial killer is most likely to have APD.
How does law enforcement use this information in tracking down a serial killer? This is where profiling comes in. A profiler does not list a specific set of attributes that will solve a case. Profiling is used to eliminate less likely scenarios, or to rule out less likely suspects that don’t fit. It enables law enforcement to focus their attention on fewer subjects, and concentrate on those who are most likely to have committed the crime.
Some event in the life of a serial killer acts like a trigger to set him off and become unhinged. It forces them to need to satisfy some deeply rooted fantasy based on something that happened to them in their past. This becomes their ruling passion. Their choice of victim/victims depends on satisfying this passion. The manner in which they approach planning and executing satisfying that need is determined in large part by whether they are classified as organized or disorganized serial killers.
Organized serial killers are usually more mature in age; thirty or older, and may be average or above average in intelligence. They may be married with children. They can and often function normally in work situations, often as outstanding performers. For the most part, they can maintain enough control over their fantasies so as to avoid being impulsive. In other words, these individuals can appear “normal” to others.
They will have a prior plan to the first phase of their attack and may actually rehearse it. They will stalk their victims who they have previously selected, and lure them through manipulation. They bring their tools of the trade with them in order to carry out their intentions. These may include hand cuffs, tape, ropes or drugs to incapacitate their victims. They will have a place already determined to dispose of the corpse, and they cover their tracks to leave no evidence behind. This comprises their Modus Operandi, or MO. It is what they NEED to do to commit their crime.
Specific types of women that fit their fantasy will be targeted. In order to satisfy this deeply rooted fantasy there are certain things they LOOK for such as: race, hair color, height, body build, age or unusual features. This becomes the perpetrator’s Signature. A killer’s Signature can change in character over time through refinement in order to escalate his core fantasy. A change in their MO is unpredictable. Due to extenuating circumstances they may have to change some facet of the execution of their crime.
Disorganized serial killers are 180 degrees opposite in their approach to committing their crimes. They do not plan them, rather they act spontaneously. This unpredictability makes it hard for law enforcement to catch them. These killers are usually of below-average intelligence or psychotic. They are socially isolated and usually live alone. They leave their victim’s bodies where they attacked them, and subject them to frenzied mutilation to depersonalize the body. There is no careful hiding or destroying of evidence that would link them to their crime. Often it is found within or on their premises in plain view. There is also another category called mixed homicide that combines organized and disorganized behaviors.
Victims in thrillers are usually depicted as too trusting or caught off guard. In real life trust your instincts. When something doesn’t “feel” right about a stranger—get out of there as if your life depended on it; because it just might.