Not sure about that. "Knowing" it and being able to prove it are two different things. With a conspiracy the only way to get evidence is from those on the inside of that conspiracy. To do that you need a carrot and a stick which only the USA enforcement agencies have. The stick is long prison sentences for financial crimes and the carrot is plea bargaining which enables you to get a reduction for helping to catch the bigger fish. That's why the American authorities are always the ones that expose the big financial scandals and our FCA and SFO have to piggyback their activities.
Knowing it and having the wherewithal to prove it. Step forward the FBI and Mr Blazer.