1. Serial Killers and Criminal Profiling

2. Typology of Serial Killers
Visionary
Feels impelled to commit murder by visions or “voices in my head.”
Mission orientated
rid society of certain types of people eg. prostitutes, runaway kids, racial group etc
Hedonistic
Kill for the pure thrill and joy of it; the majority of serial killers are hedonistic serial killers.
Power/Control orientated
Gains more satisfaction from exercising complete power over his victims, and sexual activity is almost always involved
Serial Killers (SK) are often associated with the Paraphilias (devaint sexual arousal & fetishes) and as a consequence some emphasize the importance of fantasy in creating the conditions for SK motivation:
Holmes and DeBurger Typology [1988] based on assumption that it is psycho-genic [psychologically rewarding not insanity or gain], motives are evident only to the killer in an "intrinsic locus of motives" see the usefulness of the techniques of neutralization idea and other socio-psychological theories of crime causation as well.

3. Motivation
Power Re-Assurance [Compensatory] - behavior that restores the offenders self worth and confidence.
Power Assertive [Entitlement] as above but expressed through control, mastery and humiliation while showing authority.
Anger Excitation [Sadistic] - the violence is eroticized or pleasure given from suffering - primarily sexual.
Anger Retaliatory [Anger/Displaced] - rage general , symbolic or specific often domestic violence, stranger sex assault, work related homicide etc.
Profit - material or personal gain - non-signature type & not related to any specific emotional need

4. The Organized Serial Killer
Offense planned
Victim a targeted stranger
Victim personalized
Controlled conversation
Crime scene reflects overall control
Demands submissive victim
Restraints used
Aggressive acts prior to death
Body hidden
Weapon/evidence absent
victim or body transported from scene
Associated with psychopathy

5. The Disorganized Serial Killer
Spontaneous offense
Victim or location known
Depersonalizes victim
Minimal conversation
Crime scene random and sloppy
Sudden violence to victim
Minimal use of restraints
Sexual acts after death
Body left in view
Evidence/weapon often present
Body left at death scene
Associated with Psychosis

6. M.O. = "success of crime"
I. Victim/location selection, means of attack, use of weapon, planning, means of transport
II. Valuables taken
III. Evidence left behind
Signature = "needs and patterns of offender"
I. Wound patterns, sex acts, means of control, rituals, talk
II. Souvenirs taken
III. Evidence destroyed

7. Modus Operandi: METHOD OF OPERATION (M.O.)
How the offender committed the crime.
Planning
Selection
pre-surveillance,
weapons & constraints,
precautions,
transportation etc.

8. In general, modus operandi is the behavior necessary for the successful commission of a crime.  Douglas & Olshaker define M.O. as "what an offender has to do to accomplish a crime."  At a minimum, every M.O. will contain elements that involve the following:
ensure success of the crime;
protect identity;
effect escape. 
For example, when a criminal uses duct tape to cover a victim's mouth, this is M.O. because the criminal has realized the victim's screams for help might get him caught.  You cannot always link cases by M.O. because M.O. is dynamic and always changing with experience.  It's learned behavior like any other behavior, and involves things like experience, education, and maturity. 

9. Signature
SIGNATURE
The behavior/expression of fantasy the killer must leave at the scene to satisfy emotional/psychological needs. Goes beyond what’s necessary to commit crime and tells about the offender’s psychological needs and motivation.
Usually consistent and unique
to that killer

10. Signature
In sum, signature is a combination of behaviors, emotions, and thoughts.  The signature is sometimes called a "trademark" or "calling card" and reflects a compulsion on the part of criminals to go beyond just committing the crime to "express themselves" in some way that reflects their personality. Douglas & Olshaker (1998:90) define it as "something the offender has to do to fulfill himself emotionally ... it is not needed to successfully accomplish a crime, but it is the reason he undertakes the particular crime in the first place."  Signatures usually put the offender at great risk because they must stay at the crime scene longer, so ordinary signature is often hard to detect.  At other times, it's obvious, such as when an offender goes to the trouble of leaving a Bible at the scene of the crime.