Time and time again bankers are involved in major scandals on a regular basis. Greece is also to blame in part, there should be more enforcement of tax collection and the black economy should be attacked and minimized.
The tax evasion by the oligarchs was an open secret and the governing parties of that time (PASOK and New Democracy) never bothered to take any action to prevent the monetary outflows. Now SYRIZA is in a fix. The oligarchs have moved all the money to safe heavens such as London and Geneva, and there is no way to bring that money back to Greece.