There are no pristine administrations on any pretty much any level. Very little chance he has done something that hasn't been done by any white politician's administration.
It's like getting a ticket for jaywalking in NYC. Everyone is jaywalking but a cop just enforces it on you. Also, no Black politician who is mayor of the nations largest city is gonna be reckless. He knows he's going to be looked at with a fine tooth comb.
The black politicians who have been a bit too sloppy were in cities with very large black populations at the time (Washington DC, Detroit). They thought they had cover because blacks were in charge of everything from the police dept, courts, etc.
The governor of NY state is a Democrat, the country's president (and therefore its judicial enforcement agencies) are run by Dems, so if they are coming after him there is something he's done to piss the Dems off that I am not aware of.
He's insulated by his own party so it can't be the Republicans I'm thinking. He's a tool of the powers that be anyway.