In the 1930s, the Bolsheviks created a caste of "Urkagans", the kings of the criminal world, who were created from the "ofeny", petty traders, pickpockets and crooks, to fight the Zhigansky movement of former White Guards in prisons and to "reform the nation". They called them socially close, and introduced them into the gulag system, where they collaborated with the administration and mocked political prisoners, among whom there were many children. They physically and morally crushed them, could kill or rape them with impunity. This caste weakened during the eve of the collapse of Bolshevism, after the war, during the "bitch wars", but they are still preserved. They became entrenched again during the reign of Brezhnev. And they still terrorize prisoners and even free civilians.
(Much of this can be found in the books of Solzhenitsyn, he was a direct witness to these events)