Hunt down the individuals who ran the death camps, the murderers of political prisoners, and put them on trial. Continue the hunt relentlessly for years, exactly like the Israelis did against the Nazis.
I agree, but it's not all that practical.
The massacres mostly occurred during 1950's or earlier. There was also the crackdown on the Prague Spring of 1968. Nearly everyone who was complicit in the atrocities is already dead. The handful of perps still around are going to very, very old, more than likely living in Russia, and it will be a cold day in hell before Putin lets the Czechs or any other outside nation touch them.