Criminal escalation for a serial killer is when the crimes increase in intensity or in magnitude.
The profiler should analyze the killer's propensity to escalate:
- his criminal career: some serial rapists might escalate to murder during their career, either by accident (a victim fights back an the killer discovers the pleasure that the killing brings) or by choice (the French serial Killer Michel Fourniret started killing after one of his rape victims reported him to the police and he got arrested, and wanted to make sure not to get caught again). At the same time, no serial killer wakes up one day and start killing people just like this. There is always a history that leads them to killing people, and for most of the time, the killings are the end result of a life of crime. So it is important to determine what possible criminal career the serial killer went through even before starting killing. For example, some can start by breaking and entering homes to steal people's valuables, and realizing one night that there is a woman living alone in the house and sleeping in the bedroom, can rape her. That could lead to an escalation in his crimes as he would target the houses of women who live alone and the real intention would shift from theft to rape. Later he could strangle one of his victims as she tried to fight back, but realizes how much he enjoyed the power the strangulation gave him. So a serial killer who breaks into houses, steals valuables, rapes and strangles women could have an extensive criminal record with traces of breaking and entering, theft, even maybe rape or sexual molestation themed arrests.
- his series of crimes: usually, the time between the first and the second killing is longer than between the following killings. And if the serial killer is not in control, killing is for them like drug abuse: the more they use the drug, the less the effect of the drug will last, the sooner they will need a new fix. In other words, the serial will have a shorter cooling off period every time he will kill, as the pleasure and the reminiscence of the pleasure will pass by quicker and the need to kill again will appear sooner. But some serial killers (highly organized, mature and sophisticated) can keep their urges in check and stop killing for longer periods for various reasons, such as the police being close to catch them, personal events and changes in their personal lives... This was the case for BTK who could stop killing for several years in a row.
- the intensity of each crime: this refers to the crime escalation during a specific crime. For example if the killer wants to take time and enjoy torturing but the victim does not react the way he is expecting, he might get angry, lose control, and end up leaching out his anger on his victim. This is traditionally called an overkill, meaning that the killer will use more blunt force and savagery than is necessary to kill his victims. At the same time, a serial killer can just enjoy strangling his victims for the beginning, but then as the killings go by, and his maturity and confidence is growing, he might start to spend more time torturing the victims before killing them.
It is also important to figure out the stages of the development of a serial killer, and see if he is evolving or devolving:
- an evolving serial killer is usually organized and demonstrates more maturity and more confidence with each killing. He shows an ability to learn from his experience and modify his MO to get more satisfaction from his killings. It can also describe a change in the fantasy of the serial killer. When I say change, I don't mean that he would have or develop a totally different fantasy, but rather that the more his kills or tortures, would refine his fantasy or make it more complex (a sadistic killer could first start with buying an isolated place where he could torture his victims without being disturbed, and later create and build his own torture chamber, matching his specific needs).
- a devolving serial killer is at the contrary in most cases unorganized and is totally controlled by his fantasy and his impulses. His crimes would become more and more erratic, without real purpose and usually loses complete control over reality and his own actions. The need for a victim would me more and more urgent and some might even go on a real killing spree.