A spree killer is someone who embarks on a murder "rampage". This is an ambiguous term, related to mass murderer and serial killer. The Bureau of Justice Statistics defines a spree killing as: "[involving] killings at two or more locations with almost no time break between murders." The definition is especially close to that of a serial killer; perhaps, the primary difference between the two is that a serial killer tends to "lure" victims to their death; whereas, a spree killer tends to go "hunting".

This disorder is characterized by a long-standing pattern of a disregard for other people's rights, often crossing the line and violating those rights. This pattern of behavior has occurred since age 15 (although only adults 18 years or older can be diagnosed with this disorder) and consists by the presence of the majority of these symptoms:

Failure to conform to social norms with respect to lawful behaviors as indicated by repeatedly performing acts that are grounds for arrest.
 
Deceitfulness, as indicated by repeated lying, use of aliases, or conning others for personal profit or pleasure.
 
Impulsivity or failure to plan ahead.

Irritability and aggressiveness, as indicated by repeated physical fights or assaults.
 
Reckless disregard for safety of self or others.
 
Consistent irresponsibility, as indicated by repeated failure to sustain consistent work behavior or honor financial obligations.

Lack of remorse, as indicated by being indifferent to or rationalizing having hurt, mistreated, or stolen from another.

Serial Killers , on the other hand, do not kill their victims all at once, but rather over a period of time.

Affective Dimension
Need for stimulation/-proneness to boredom
Parasitic lifestyle
Poor behavioral controls
Early behavioral problems
Lack of realistic, long-term goals
Impulsivity
Irresponsibility
Juvenile delinquency
Revocation of conditional release

A mass murder (massacre) involves the murder of large numbers of people either by a state or an individual. This should not be confused with serial killers, who usually tend to kill one person (or perhaps two) at a time.

Psychopaths do not suffer from hallucinations but from a character flaw. These types of serial killers are in touch with reality and know right from wrong. They just don't care. Psychopathic serial killers lack one very important component of human nature - a conscience. Either they have no conscience, or their conscience is too weak to inhibit the violence they commit. Psychopaths kill without guilt and remorse.

One of the most frightening aspects of a psychopathic serial killer is his/her ability to blend in with his/her environment. The person seems normal. However, beneath the surface lies two uncontrollable traits: sexual abnormality and a consuming need for power. The killings satisfy both, with the ultimate control over life and death. Simply stated, killing gives them pleasure. They kill, experts say, because they want to and because they like it.

Studies statistically show that a serial killing crime can be defined with characteristics such as:

Categories include: psychotics and psychopaths .

Theoretically, psychopathy is a three-faceted disorder involving interpersonal, affective and behavioral characteristics.

Three to four victims, usually with a "cooling off" period between victims.                                                                                                   
The killer is more than likely a stranger to the victim, so the murders appear as though they are unconnected or done at random.
The serial killer has a sadistic urge to dominate the victim.

There is usually no profit to be made from the victim, except for the psychological satisfaction of the killer.

The killer usually selects a victim who is vulnerable.

The overwhelming majority of serial killers are white males, in their 20's or 30's, lower to middle class background, and of at least average intelligence.

Some serial killers have a fascination with law enforcement or an authoritative figure in general.

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