In 1978, the FBI set up a Behavioural Science Service Unit in Quantico, Virginia. At this centre, serial killers are studied, and profiles are compiled on suspects. This information in turn allows the FBI to do profiles of cases that are brought to their attention. Through studying the case, including the manner in which the killer murders his victim, who the victims are, how the body was left, etc., the FBI comes up with a "description" or a profile of what the killer is probably like. Profiles include things like what the killer's age is, his race, his social ties, some of his personal characteristics, etc.
The first time a profile was ever used was in 1957 in the New York case of the Mad Bomber. The profile said that the offender would be: heavy set, middle aged, foreign, Roman Catholic, single, living with a brother or sister and would like double breasted suits. The profile was right except for the fact that the offender lived with 2 sisters. This does not mean that profiles are always right on. Some can be vague. The profile for Arthur Shawcross, who killed several women in Rochester, said he was 15 years younger than he actually was. Critics of these profiles worry that the police will become to literal in their interpretation of the profile, and therefore search only for people who match the profile, whether or not they are the killer.
The following list of traits is the factors most commonly found in serial killers. While not every serial killer will have all of these qualities, there is a good chance they will have some if not most.
- 25-35 years of age
- white males (85%) (there have been very few documented cases of female serial killers)
- kill same type of victim in same way
- possibility of physical deformities (i.e. webbed feet)
- average or above intelligence
- abuse as child/dysfunctional childhood
- few social attachments
- interest in violent pornography, bondage equipment, detective magazines (83%)
- keep records of offences (53%)
- no arrest histories (57%)
- history of some kind of head/brain injury
- alcohol/drug abuse
- mobile; travel frequently
- follow crime story in media
- like the publicity/notoriety
- kill within their own race
- may return to scene of the crime or burial
- compulsive/obsessive (i.e. multiple showers a day)
- keep souvenirs or body parts of victims
- likely to have been interviewed by the police in the serial killings investigation
- sadistic treatment towards animals as a child
- play with/start fires as a child
- work alone (about 25% of serial killers have a partner or group)
It is amazing what the FBI can tell about a person just from examining how the victim was killed, and what was done to her/him before death. For example, if the killer strangles his victim, it may indicate a need to be intimate with the victim. If the killer shoots the victim, it indicates a desire to remain remote or distant from the victim. If the killer "overkills" the victim (i.e. stabs the victim multiple times), that may indicate that he felt powerless and was trying to show his dominance. If the victim is mutilated after death, the killer was likely afraid or ashamed to face the victim alive. If he killed the victim after mutilation, he was likely trying to gain control over the victim. If he spent a long time at the scene, then he was confident, and likely older. If he was in a rush, he was likely younger. If the murder was very brutal, it may indicate that the killer has feminine characteristics. If he sexually assaulted the victim after death, he was shy.