Typology Approach

The FBI Top-Down Approach

The top-down approach to offender profiling was developed by the FBI's Behavioural Science Unit in the 1970s and 1980s. It is described as "top-down" because investigators begin with a pre-existing typology — a set of offender categories derived from research — and use crime scene evidence to place the unknown offender within that typology. The approach was based on in-depth interviews conducted by Douglas, Ressler, Burgess and Hartman (1986) with 36 convicted US serial murderers, including Ted Bundy and Charles Manson.

The Organised/Disorganised Typology

Hazelwood and Douglas (1980) classified murderers into two types based on crime scene evidence. Profilers examine evidence at the crime scene — the state of the body, presence of forensic evidence, use of restraints, choice of victim — and use it to infer whether the offender is organised or disorganised. This classification then drives inferences about the offender's background, occupation, relationship status, and likely next move.

Organised offenders plan their crimes carefully and leave little forensic evidence; they are typically employed, in a relationship, and of above-average intelligence. Disorganised offenders act impulsively, leave significant evidence, and are typically unemployed, socially isolated, and of below-average intelligence. A mixed category was later added for crime scenes showing features of both types.

Application and Process

The FBI profiling process involves four stages: (1) data assimilation — gathering all available evidence; (2) crime classification — placing the crime in the organised or disorganised category; (3) crime reconstruction — hypothesising the sequence of events; and (4) profile generation — producing a description of likely offender characteristics. Ressler et al. (1986) reported that the approach contributed to solving a number of high-profile US serial murder cases.

Evaluation

Canter, Alison, Alison and Wentink (2004) subjected the organised/disorganised distinction to empirical testing by analysing data from 100 US murders using smallest space analysis. They found that all 39 features defined as "disorganised" were actually more common in organised crime scenes than the model predicted. The clear dichotomy was not supported — most crime scenes show a mixture of features, undermining the validity of the entire typology.

Further limitations include the small, unrepresentative sample on which the typology was built (36 murderers; all US; all already convicted). The data were retrospective and self-reported, and FBI agents selecting and interpreting the data may have introduced confirmation bias. The approach is also largely restricted to serial sexual murder and does not generalise to other types of crime (burglary, fraud, terrorism). It has been criticised as more art than science, with no standardised, replicable procedure.