The night of the long knife 1938
Hitler split with and purged the SA brown shirt, and the violent prone Rohm, his old friend. Getting rid of the old militia is to win the legitimacy of governance. Same applies to the higher echelons of communists. Why did they decide to purge the members of the former partizans and the fifth column they had created? Those people were now rendered useless and needed to be gone. History could be rewritten if the witnesses are gone. And that part of the history wasn't so glamorous: being the thieves and robbers was not glamarous. They have stolen the power from the Chinese people.