Homicidal children and adolescents often have learning difficulties and language delay. Psychotic disorder in juvenile homicide is unusual but paranoid ideation is not uncommon. Substance abuse, in particular alcohol and drug abuse, is common and becoming an increasingly significant trigger in serious acts of violence by adolescents. The three main psychological theories and explanations of violence and sadism in the young - psychodynamic, behavioral and a humanistic existential perspective - all attribute the abnormal behavior to a young person's maladaptive attempt to deal with an ultimate sense of personal failure. Contributory socio-cultural factors include: prolonged separation from the mother during the first years of life; severe physical abuse; sexual abuse; exposure to repetitive or extreme violence; and parental mental illness. Behavioral scientists are increasingly concerned also about the availability of weapons and the quantity and level of response of children to media violence. The paper discusses the evolution and role of fantasy and types of intervention. References