Findings of the study indicated that those in the early-onset group who began offending prior to the age of 13, were more likely to have experienced significant problems in childhood and adulthood; those in the no-offending group with no previous convictions prior to committing a murder, were the least likely to have had problematic backgrounds; and those in the late-onset group who began offending after the age of 13, had childhoods which resembled the no-offending group, but an adulthood that more closely resembled the early-onset group. A dataset of 786 case files of men from the Murder in Britain Study was examined using bivariate analysis and Multiple Correspondence Analysis (MCA). Different types of murder were examined in terms of a number of theoretically and empirically derived constellations of factors previously shown to be associated with homicide, such as relationship between victim and offender, demographic and socioeconomic characteristics of offenders and victims, childhood and adult background, circumstances prior to the offense, and contextual and situational factors at the time of the murder. Data were coiled from three sources: the existing national homicide indexes for England/Wales and Scotland; primary data gathered from the case files of a sample of men and women convicted of murder; and in-depth interviews with men and women currently in prison for murder. All original data was gathered, coded, and analyzed by a team of four senior researchers with many years of experience studying violent men and female victims of violence. The findings for developmental criminology and homicide research, and the implications for policy and intervention are discussed. Tables, figures, notes, and references