THE MURDERERS IN THIS STUDY ARE NOT TOTALLY REPRESENTATIVE OF MURDERERS IN GENERAL, AND NO STATISTICAL ANALYSIS IS ATTEMPTED. ALL EXCEPT ONE FEMALE WERE BLACK AND OF LOW SOCIECONOMIC STATUS. THE 10 TYPE A MURDERERS HAD A TANGENTIAL OR INCIDENTAL RELATIONSHIP WITH THEIR VICTIM; THE 7 TYPE AB MURDERERS FORMED SUSTAINED RELATIONSHIPS CHARACTERIZED BY DEEP DEPENDENCY WITH STRONG SADISTIC TRENDS TOWARD THE VICTIM; AND THE 4 TYPE B MURDERERS MAINTAINED PROLONGED, LONG-SUFFERING RELATIONSHIPS WITH THE VICTIM BEFORE THE MURDERS. IN TYPE A MURDERS, ALCOHOL AND IMMEDIATE WEAPONRY WERE ESSENTIAL ELEMENTS. DIAGNOSES SHOWED A SCHIZOID, INADEQUATE, PASSIVE-AGGRESSIVE OR EXPLOSIVE PERSONALITY, AND PREVIOUS HISTORIES OF VIOLENT BEHAVIOR. EARLY PARENTAL LOSS AND DEPRIVATION OCCURRED IN MOST CASES. TYPE B MURDERS WERE VICTIM-INDUCED. THE MURDERER, USUALLY A WOMAN, OFTEN WAS THE LONG-SUFFERING SUBMISSIVE PARTNER OF A CONTROLLING, SADISTIC HUSBAND OR BOYFRIEND. UNLIKE TYPE A, REMORSE WAS USUALLY PRESENT. TYPE AB MURDERERS SHARED MANY OF THE CHARACTERISTICS OF TYPE A MURDERERS BUT COULD SUSTAIN A RELATIVELY ENDURING THOUGH SADISTIC RELATIONSHIP WITH THE VICTIM. THEY WERE CONSIDERED THE MOST DANGEROUS AND MOST AT RISK TO MURDER. PSYCHIATRIC INTERVENTION WAS SEEN AS HELPFUL IN EXPLORING ALCOHOLISM AND THE NEED FOR WEAPONRY IN TYPE A AND AB MURDERERS AND IN TREATING GUILT AND SUICIDAL IMPULSES IN TYPE B MURDERERS. VARIED TYPES OF TREATMENT, GUN REHABILITATION PROGRAMS, AND ENCOURAGING OTHER FORMS OF AGGRESSION (JUDO, BOXING) MIGHT AID IN PREVENTION AND FURTHER RESEARCH INTO VIOLENT BEHAVIOR SHOULD BE ENCOURAGED. TABULAR DATA AND REFERENCES ARE GIVEN. (AOP)