In the former Soviet Union, when it crumbled, KGB agents quickly became mobsters.
Information is power, and those with lots of information -- FBI and KGB and CIA and the like -- are always able to exert said power.
Especially when they are protected by secrecy. That is why I say, as soon as those organizations were created in the United States, there was no way to control them, and we sentenced our freedom to death. The only way to have a free country, is to have a decentralized government, and to have a place in the world that doesn't require such organizations. It's too late now. The first HUGE blow to liberty was the centralization of the Federal government in 1865. WWII was another HUGE blow. Hitler succeeded in making us Socialistic, after all.