The objective of the study is to assess the relationships between personality traits, lifetime psychosocial functioning, and crime scene behavior. Thirty-five male offenders referred for forensic psychiatric assessment in Sweden (1996-2001) and assigned a main diagnosis of either antisocial personality disorder (APD) or autism spectrum disorder (AUT) were retrospectively studied. APD were subcategorized into impulsive (APDi) and controlled (APDc). Those in the AUT group were less intoxicated at the time of the crime and did not often use knives or guns compared to the APD group. Males in the APDi group were older and had a higher proportion of abuse of alcohol and drugs in biological parents, physical abuse during childhood, psychiatric contacts, and suicide attempts compared to the APDc group. In the APDi group, knives were used in the homicide compared to the use of guns in the APDc group. The results suggest differences in psychosocial functioning and crime scene characteristics related to personality traits. (Contains 2 tables.)