An interdisciplinary team examined data gathered by law enforcement personnel regarding the crime scene, circumstances, backgrounds of all participants, neighborhood conditions, instigating circumstances, and interpersonal relationships. The perpetrators were a 26-year-old man who shot his mother, stepfather, and stepbrother; a 40-year-old father who shot his wife, his twin daughters, a 34-year-old man who rented a room from the family, and himself; and a 29-year-old woman who shot and killed her three children and herself, in all three cases, the perpetrator was a member of a cultural or social group that placed great emphasis on status and saving face and had made previous threats of suicide. All the perpetrators had also suffered a recent deep depression as the result of a failed love relationship, had in some way been separated from the family unit, and had made threats against family members or others. The perpetrators were all using alcohol or other drugs at the time of the crime. Analysis of four other cases confirmed the importance of these factors. The following strategies should be considered for preventing family homicide: (1) early arrest of perpetrators of family violence or abuse, (2) referral for help in cases of repeated incidents, (3) court-mandated counseling for repeat offenders, and (4) public education regarding danger signs and help line numbers. Tables and 2 footnotes.