Were leaders who came to power in Russia of the "Communist party" really just a group of mafia thugs?

They were Marxist Socialists, and they were able to come to power because of the gross negligence and tyranny of the Tzar's. They initially had good intentions, to rid the country of the tyranny and run it for the people, by the people. But Socialism of the Marxist-Communist type leads inevitably to what happened in Russia, China, and the current and best (or worst) example, North Korea.