With multiple scandals swirling around Mayor Bill de Blasio, one such investigation involves an attempt to flip the state Senate to Democratic control, something the Mayor tried unsuccessfully to do in 2014. The Mayor's involvement in specific state Senate races continues to be a flashpoint between de Blasio and State Senate Republicans who have not seemed eager to work with the Mayor ever since. State House Reporter Zack Fink has the story.

In 2014 Governor Cuomo was up for re-election. So was the entire State Legislature, including the Republican controlled state Senate. Mayor de Blasio immersed himself into a handful of Senate races to flip control of the upper house including those of Terry Gipson, Cecilia Tkaczyk, and Justin Wagner, all of whom were Hudson Valley Democrats, and all of whom lost.

"It's a very high risk strategy because if he wins maybe he can influence legislation but there is still the Governor and there is still the Assembly, and if he loses, which he did, he just gets everyone mad," said Steven Cohen of Columbia University.

Republicans never forgave de Blasio for political activities he directed against them. The mayor doesn't deny working on behalf of those Democratic candidates but how it was done has now come under scrutiny from the Manhattan District Attorney's Office and the U.S. Attorney.

Insiders say the Mayor set up an entire political operation, and the investigation focuses on whether that operation circumvented direct contribution limits to candidates by wheeling large sums of money to local county committees which then spent that money on behalf of the candidates. Experts disagree whether this is a violation of the law, something that is done all the time in politics, or a grey area that has yet to have solid test case.

"Putting aside all of the legalities of this, which there may be serious ones, it was unethical," said Dick Dadey executive director of Citizen's Union. "I mean for the Mayor to be so involved in the State Senate races and to be raising money that is then spent by evading regular campaign finance rules and going through these County committees, The Mayor of the City of New York should be setting an example."

The U.S. Attorney is coming off two major victories last year with the convictions of legislative leaders in both houses. As for the case against former Assembly Speaker Sheldon Silver, some believe he was convicted on thin evidence.

 And the same U.S. Attorney's office recently argued to release damning information about extramarital affairs Silver had, which further eroded public perception of his character ahead of sentencing which is scheduled for next week.