Two cases are presented of teenage perpetrators of homicide, exemplifying the more and more widespread phenomenon of committing such crimes without any important or comprehensible motives (of not psychopathological nature though). Sources of such motives (e.g. in order to gain unusual experience, or peer group acceptance) and their relation to perpetrators' personality are analyzed. Moreover, possible detrimental influences of some large-scale social and cultural phenomena on psychological development of children and adolescents are considered. Finally, the authors deal with the issue of difficulties in psychological assessment and formulation of psychiatric court opinions in such cases.