At some point the responsables will want to travel abroad, visit some other country or even move from Russia to another country. As recently as a few months/years I read about war criminals from WWII being condemned, some of them in their 90s. Nobody will go after the current war criminals in Russia from outside, but maybe, in 10 - 20 - 30 years Russian people will decide they want to live in a democracy and apply the rule of law themselves.