Classifying homicide offenders and predicting their characteristics from crime scene behavior.

A theoretical distinction between instrumental and expressive aggression was used in analyzing offender characteristics and their associations with crime scene actions in Finnish homicides. Twenty-one variables reflecting the offenders' criminal activity, previous relationships with intimates and victims, and general social and psychological adjustment were derived from files of single-offender/single-victim homicides occurring between 1980 and 1994 (n = 502). Additionally, three variables describing post-offense actions and police interview behavior were included.