Homicide-suicide is a tragic phenomenon which typically does not result in a criminal charge or trial. However, correct diagnosis and classification of homicide-suicide cases are important to determine the perpetrators and dynamics of each category properly. The deaths in the homicide-suicide acts can be divided into two categories with respect to the number of involved individuals: dyadic deaths and triple or multiple deaths. These two categories can also be divided into two subgroups according to the chronology of the incidents: simultaneous deaths and consecutive deaths. Herein, a simultaneous homicide-suicide case of a father and daughter where both deaths occurred through drowning which was not found in the selected literature review and where the victim was a child is presented. The article aims to clarify the term discrepancies about multiple death cases in the literature and to discuss the pathological and psychosocial characteristics of the simultaneous dyadic death cases.