Results extend previous findings on the development and prediction of violent criminality among incarcerated offenders. The results suggest clear differences in the criminal behavior patterns of the three participant groups, with those involved in the most serious types of violence (murder and attempted murder) displaying the most precocious, varied, and frequent crime. In addition, those who had committed murder and/or attempted murder had a disproportionately high tendency to deliberately hurt animals during their formative years. Inmates who had attempted or committed murder committed their first crime, on average, as preadolescents, whereas inmates who had not committed violent crimes committed their first crime, on average, in their midteens. Inmates who attempted or committed murder were raised in families considerably more deviant than families of the other two groups. Lastly, commission of violent crimes is associated with a higher current level of anxiety. Proponents of the criminal career perspective emphasize that there are different dimensions of criminal activity, such as type, onset, participation, frequency, and seriousness and that each dimension may require a separate explanatory model. The purpose of this study of 183 drug-abusing inmates from Baltimore, MD was to determine factors that discriminate among offenders who (1) have no history of violent criminal behavior, (2) have a history of violent criminal behavior but have never attempted or committed murder, and (3) have attempted or committed murder. Specifically, three questions were addressed regarding violent criminal activity. First, what is the relationship between various early family and developmental factors and the adoption of a violent criminal lifestyle? Second, can a drug abuser’s drug use history predict violent criminal activity? Third, are there different patterns of psychological functioning in violent than there are in nonviolent criminals? Tables, references