The mark of Cain: the russian criminal tattoo, episode 3. The first episode can be seen here and the second episode can be seen here.
Extras from this episode: The lowest category in the criminal world are the so-called Downcast. The men in the colony who fulfill, mostly by force, the female role. [...] These people (the Downcast) live separately, they eat separately,they sit apart in the mess hall. They don't have the right to look in the eyes of the other convicts. [...] Sometimes they have humiliating words (like slave, or bitch) tattooed on their faces, so they can be easily recognized when they arrive in a new prison.