``Like Greek heroes, heroes of modern tragedies live according to the will of their prophet parents, whose prohibitions limit their options and whose curses lead them to a tragic possibility of self-destruction, which often times bears that horrible and unrepairable stamp of Cain.'' This is what Leposava Kron wrote in the book ``Cain's Sin: Psychological Typology of Murderers,'' still hot out of the press by ``Prometej'' and the Institute for Criminological and Sociological Research in Belgrade