know where the bodies are buried
know where (all) the bodies are buried
To know everything about someone or group, especially secret things that they might not want to be revealed. Usually used in relation to someone who wields this information for their own benefit or advantage. I've been an accountant with this company for over 50 years, so trust me, I know where all the bodies are buried. He climbed to power because he knew where the bodies were buried for every single person at the top of the government and the military.