Quis custodiet ipsos custodes? - this a Latin proverb meaning "who will guard the guardians?" or "who will watch the watchdogs?"
Correct me if I'm wrong - but in a democracy, that is the job for the People, the Citizenry, the Electorate, or the body politic. That's us. We do. Or don't - depending on what little laws or obstacles those elected to power roll in the way to obstruct our view of what they are up to, post-fact. Or of course, unless they are lucky enough to have an electorate too apathetic to give a rats ass what they do in our name, be that for us - or to us.