This paper describes the consequences of an act of murder and murderous phantasies in a family seen in weekly therapy by male and female co-therapists. We shall discuss details of sessions with the family in order to illustrate various themes, in particular, the way that a murder affected the object relations of the individual family members and thus the family dynamics; the difficulty the family experienced in coming to terms with the loss of the murdered mother; and the role that perverse sexuality seemed to have in preventing adequate mourning for the mother. The two main hypotheses suggested here are: (1 ) When there is a strong mur derous phantasy, or an actual murder in the family, there may occur, during the phase of regret and remorse, a life-risking psychosomatic symptom which symbolizes an identification with the attacked or murdered person. (2 ) Perverse sexuality may be used to fend o ff experience of damage and loss which has occurred either in phantasy or in actual life , because experience of the damage and loss presents such a new catastrophic shock to the psychic structure of the people involved. We think that these hypotheses have consequences for understanding family dynamics, individual pathology and the predisposition to murder.