The huge pdf these notes are from is worth reading if you're interested in specifics; I didn't copy over anything detailed about the crimes they solved by using criminal profiling. I also don't know when these articles were originally written.
Criminal Profiling articles in the FBI archives
The meta/notes below are taken from the first two scans out of seven (I may or may not ever get around to looking through the rest).
Criminal profiling is basically behavioral science for the purpose of solving crimes. It's useful for a number of things, not just solving murders, but also in dealing with hostage negotiations or dealing with threatening letters.
Letter Writing
Some methods used in dealing with threatening letters. Every word in message is assigned to threat dictionary, compared to words found in ordinary speech and writing, used to figure out stuff about whether same person wrote letters or not [think the questions about whether all the jack the ripper letters were all written by same dude; people think probably not] figure out the signature words of the offender [i.e. shinigami] > used to figure out stuff about background. [where person came from I assume, as far as dialects etc or education levels]. This would certainly have been used when dealing with Misa as the Second Kira.
General Observations from the PDF
Crimes with a clear motive are easier to profile. Kira would actually have been an easy one for L, as the clear focus only on criminals would lead to the obvious assumption that Kira had some sort of connection with law enforcement, only added to by the leak early on in the show, which was combined with his showing-off nature. Then, during surveillance when Light showed the exact same characteristics, no wonder he suspected him.
Profilers lots of times work from photographs & preliminary reports/evidence & don’t always visit crime scenes. L mentions how he usually works apart from the scene, and in Another Note/the BB Murder Case you see how he likes to use investigators on the ground as well as evidence sent to him. Stuff such as where body was, murder weapon, signs of struggle, etc / even when people try to pass of one kind of crime for another there are usually inconsistencies. Woman killed in home with no sign of struggle, had been drinking, supposed sexual murder but no physical evidence of that? Husband did it as crime of passion, washed off hammer in sink & tried to play it off.
Criminal profiling often leads to suggested interview techniques. L realized early on that Kira couldn’t resist showing off to look smart and to taunt the investigators, so created an interview process with the tennis game and then the pictures that would lead Light to do the same if he were Kira. Light, even knowing what L’s tactic was here, still fell for it.
Criminal profiling uses brainstorming, intuition, educated guesswork, and familiarity with a large number of cases. The profiler creates hypothetical formulations—that is, a concept that organizes and explains information from crime scene data & the profiler's knowledge of other crimes.
Useful Information for the Criminal Profiler
Complete synopsis of crime, description of crime scene, time of incident, weather conditions, political and social environment. Complete background information on victim. Domestic setting, employment, reputation, habits, fears, physical conditions, personality, criminal history, family relationships, hobbies, social conduct. Forensic information. Autopsy report with toxicology/serology results, autopsy photographs, photographs of cleansed wounds. Medical examiners findings, impressions of estimated time of death, cause, type of weapon, suspected sequence of delivery of wounds. Additional aerial photographs, 8x10 color photographs of crime scene, sketches showing distance, direction, and scale, maps of the area.
What can this tell the profiler?
This evidence can reveal level of risk of the victim, the degree of control exhibited by the offender, offender’s emotional state and criminal sophistication. [the being away from crime scene of Kira, on top of the targeting of criminals, would add to that whole hands off/judgment from above thing that lead to L suspecting he had a god complex] WHAT NOT TO HAVE. Stuff about possible suspects, as that may bias the profile/investigation.
This information must be organized into meaningful patterns.
Here's an image of the criminal profile generating process that's pretty interesting:
Types of Murder
Homicides are classified by type and style. Single homicide = 1 victim/event. Double homicide = 2 victims, 1 event/location. Triple homicide = 3 victims/1 event/location. Above that, classified as mass murder.
Types of mass murder are classic and family. Classic is a person acting in one location or period of time. Mental issues lead to violent lashing out against people who may not have anything to do with his problems. Shootings where people open fire on bystanders is a classic mass murder.
Family is if more than three members of the perpetrator’s family is killed. If perpetrator takes his own life, it’s classified as a mass murder/suicide. Without suicide & with four or more victims, it’s called family killing.
There are also spree and serial multiple murders [not considered mass murders]. A spree murder is killing at two+ locations with no emotional cooling-off period in between, and considered all part of a same event, which can be long or short duration. A dude took a gun, started walking through the neighbourhood and killing people for 20 minutes. It’s classified as a spree, not mass murder, because he changed locations.
Serial murderers. That is 3 or more separate events with emotional cooling off between events. [I have a feeling that Light would have been considered a spree murderer for the first five days he had the death note. Evidence that it was a single event and he didn’t spend much time thinking about it: he filled so many pages, lost five pounds, wasn’t sleeping, and was still in a manic state when he first met Ryuk]. After that first week, he would be considered a serial murderer. This type premeditates his crimes, fantasizes about them, etc. We’ve got the bus-jacking incident and all the experiments he does; it’s very premeditated. The serial murderer, after cooling off from last victim, proceeds with plans. This cooling-off period can be days, weeks, or months. But there are also other differences between this type and other murder types.
Classic mass murderers and spree multiple murderers are not concerned with who their victims are. A serial murderer on the other hand, selects a type of victim, and thinks he will never be caught. The serial murderer controls the events. Serial murderers may commit spree murders too. For instance, if tracked by law enforcement/hunted down. The change comes about with lack of cooling-off period, and happens because murderer is feeling desperate. Light changed from a serial murder to a spree murderer when he killed the FBI agents going after him.
Possible Motives of Murders
It's important to figure out the primary intent of the murderer. Killing itself might not be the intent. The intent may be criminal enterprise, emotional, selfish, or cause-specific, or sexual. Criminal ones include where money is the object, contract murders, gang murders, competition, and political ones.
Emotional, selfish, or cause-specific include self-defense or compassion, mercy killings/life support disconnection; family disputes may lie behind family killings, paranoid reactions can lead to murder. Symbolic crimes or psychotic outbursts. Even assassinations. Religious, cult, and fanatic groups. Sexual ones pretty self-explanatory.
Risk Factors and What it Says about the Murderer
Victim risk can lead to stuff about how murderer is choosing victims. [high risk = bus depots, isolated areas, etc, plus other things that would make victim an easier target].
Offender risk is how much risk the offender had of being caught, and can generate assumptions about how he works. For instance, a low-risk victim sought under high-risk circumstances leads to ideas that criminal may not feel he will be apprehended, stresses, needing excitement, maturity level.
Light changing the times he killed people in response to their information about Kira is adding to his risk level by taunting them, it shows he needs excitement and that his maturity level is low. Although L already knew this from the Lind L Tailor broadcast. This is why L felt confident in saying that if they stopped Kira from killing criminals by ceasing broadcasts, he would probably move onto regular people. He’s recognized that this is partially an adrenaline/power-play thing.
Misc.
Escalation. Look at sequence of facts to predict possible escalation of crimes. In the Kira case, L refuses to pressure media to stop giving out criminals' names and faces fearing that it would lead to an escalation of Kira's killings.
Time factors. Length of time needed to kill the victim [with the Lind L Tailor broadcast, L discovers this can happen in real time]
Location factors add to details about offender. L uses the Lind L Tailor broadcast to quickly narrow down where Kira is operating to the Kanto region.
The Crime Assessment Stage
Crime assessment stage. Reconstruct series of events, behavior of criminal and victim. Assessments made about classification of crime, organized/disorganized aspects, offender’s selection of victim, sequence of crime, strategies to control victim, staging (or not) of crime, motivation for crime, crime scene dynamics.
Organized vs Disorganized
Organized murderer plans out his crimes, chooses victims carefully, controls his victims, acts out violent fantasies, etc / disorganized is less planned, victims are more random & it may have less to do w fantasy than psychotic impulses. Knowing this can lead to knowing if crime was staged to look like a type of crime it wasn’t. If it’s staged in such a way that you can tell criminal had knowledge of police procedure that leads to knowing there is law enforcement background and that true motive/type of crime may be different than it appears. For instance, rape-murder disguised as extortion to throw law enforcement off his tracks.
Motivation easier to gather from an organized crime/planned out thing.
What to do next?
Create criminal profile, including how criminal will respond to different investigative efforts. Demographics, physical characteristics, habits, beliefs and values, pre-offence behaviors, plus recommendations for interviews/apprehension. Then, suspects are evaluated. Then, get suspect to confess.
The crime scene [what’s there] can show if criminal brought anything, that is, if it was planned or not. This can be different than death scene place. Weapons of opportunity imply that crime was not premeditated.
Task forces are assembled to deal with specific crimes.
If well publicized and offender knows police will get to him [since in the a case referenced in the PDF it means he’d lived or worked in same building] profilers concluded he would probably inject himself into investigation, appear helpful, but actually be seeking information. [Light’s cooperation with the investigation actually a mark against him once it has been narrowed down to someone associated with the task force].
There is no need for the confession if you get the physical evidence [in the case in the PDF, teeth impressions matched. Or, in Kira case, Misa and the DNA matches on the envelopes. The confession L wants to get from her is not to prove that she is the Second Kira—that is already proven—but to find out her method and to try to prove that Light was also Kira.]
At time this was written, they were starting databases about crime types based on interviews with incarcerated felons of different types. [They would certainly start a Kira database where they kept patterns of his kills/times/types/anything they could get about it.]
Observations about Personality Disorders and the DSM (direct quote)
“There are many types of ‘normal’ and ‘abnormal’ behavior. Many of these behaviors may have a label attached to them by behavioral scientists. It is most important to bear in mind that such a label is merely an abbreviated way to describe a behavior pattern. It is nothing more than a convenience by which professionals communicate. The important aspect is the specific characteristics or symptoms of each person. The symptoms are revealed in the way the individual ‘acts out’ and in the responses which the individual may make to the professional. The labels may differ from doctor to doctor because they are simply each doctor’s interpretations of the symptom.
"A symptom, then, is the ‘visible evidence of a disease or disturbance,’ and a crime, particularly a bizarre crime, is as much a symptom as any other type of acting out by an individual. A crime may reflect the personality characteristics of the perpetrator in much the same fashion as the way we keep and decorate our homes reflects something about our personality.”