In Russia, I can say an example how inside prison turned on mobsters. Almost everyone has heard of Alexander Solonik. His gangs - Kurganskaya three leaders were leading their hitman brigade. On the outside they were big bosses and influental. They were responsible even for killing Thieves in Law. Well when they got in prison, who runs the prison? Thieves in Law. So all of them got beaten to death on the inside.
I also read about a theory that at least one of them (Oleg Neliubin I think) was killed on Sergei Butorin's orders, so he couldn't talk. Some informant said Butorin simply made a call to one of the many illegal phones in prison.
