Given that the bulk of them would have fled around '45 or a little later, and most would have been at least in their early to mid 20's (many were older and high-ranking), anybody left now would have to be well into their 90's. I think that realistically, all of the high-profile targets are long gone, and there's only the odd low-level minion that may still be found; even so, that window is closing fast.
"Every normal man must be tempted at times to spit on his hands, hoist the black flag, and begin to slit throats."
--H.L. Mencken, The Sage of Baltimore
The Communists are responsible for more murders than the Nazis, and a large number of Communists with blood on their hands are still walking around. For some reason, nobody shows much interest in hunting them down.