We probably all have our own individual definition of what “makes” a serial killer. Ask someone the definition of “serial killer” and they’ll probably give a simplistic answer: a guy who kills a lot of people. But from a purely scientific point of view, there have been female serial killers too. The FBI defines a serial killer as a person who has killed three or more murders in more than a month. There is generally an “emotional cooling off” in between kills.
Why is this the definition? It’s actually simple to understand. The FBI doesn’t want to lump one-time mass murderers and super shooters in the same category as the people who plan more methodical killing sprees over a longer time period. There are a couple reasons for this. First, someone who commits mass murder in a single day is usually caught or killed very fast — and serial killers are usually smart enough to evade capture for longer periods of time.
Second, serial killers are active over a longer period of time because they like what they’re doing. One-time mass murderers might have planned everything out, but they’re usually people venting against society. Serial killers don’t really fit the same mold.
There are four types of serial killers. The “visionary” generally believes that he has been purposed to kill by a higher power. These guys are usually your run-of-the-mill whack jobs who hear voices.
The “mission-oriented” killer does so in order to dispatch a certain marginalized group in society. For example, if a white guy searches out only African American victims, he’s all about the mission. Another sicko.
The “hedonistic” serial killer is in it for personal pleasure. These are the guys (or gals) who liken the act of killing to an orgasm. These killers are more likely to rape, torture, or steal a wad of cash before they off the victim.
The “power” hungry serial killer is in it because murder makes him feel like he’s in control. He’s doing it to dominate and subjugate victims, who might be younger or older, because plain ‘ol S&M just doesn’t do it for him.
Herbert Mullin was a “visionary” serial killer who operated between 1972 and 1973, when he killed 13 people. He thought the voices in his head would cause an earthquake in California if these particular people weren’t sacrificed for the greater good. The fantasy was a bit more elaborate, of course.
You see, Mullin thought that the earthquake had always been a threat. It was only staved off due to the perpetual bloodshed around the same time, i.e. the Vietnam War. When the war began to taper off around 1972, it was up to him to keep the sacrifices going.
Serial killers target anyone and everyone (ask these lawyers: https://www.socalinjurylawyers.com/) from the young to the old. They usually escape detection for long periods of time because they have the tendency to commit murder infrequently and without any obvious pattern. The lack of evidence doesn’t give detectives much to go on, and the longer a serial killer is operational, the better he gets at his “craft.”