After months of investigating, city and federal prosecutors have decided not to bring corruption charges against Mayor Bill de Blasio. NY1's Grace Rauh filed the following report.

There's no question it is good news for Mayor Bill de Blasio. Federal and local prosecutors announced, almost simultaneously, that they will not file criminal charges against the mayor or his aides.

"I feel it confirms what I've said all along, that we handled things in a legal manner, ethically appropriate manner, throughout," de Blasio said.

The mayor's conclusion did not match that of prosecutors, though. Acting U.S. Attorney Joon Kim wrote that the office investigated "several circumstances in which Mayor de Blasio and others acting on his behalf solicited donations from individuals who sought official favors from the city, after which the mayor made or directed inquiries to relevant city agencies on behalf of those donors."

In a letter to the state Board of Elections, Manhattan District Attorney Cy Vance said his decision not to bring charges is not an endorsement of the conduct at issue; indeed, the transactions appear contrary to the intent and spirit of the laws

"A year-long investigation by multiple entities resulted in, from my point of view, a very clear result: nothing was done that was illegal and inappropriate. Period," de Blasio said. "I think we need to put it behind us and get back to work."

Prosecutors were trying to determine whether donors to the mayor's campaign and outside nonprofit group got official favors in return. And they were examining his efforts to raise money for state Senate candidates in 2014.

"While his conduct been ruled not illegal, it clearly was unethical," said Dick Dadey of Citizens Union. "What he had done was to create a pay-to-play culture, or atmosphere, here at City Hall when not every citizen was treated equally. 

At a testy news conference, one reporter pressed for a full accounting of every interaction the mayor with city government on behalf of a donor.

"The issue has been exhaustively investigated," de Blasio said. 

The mayor says he did not get any advance notice about the conclusion of the cases. He was at the gym in Park Slope when he first heard the news.

The unusual decision by prosecutors to publicly announce that they would not bring charges comes less than a week after former U.S. Attorney Preet Bharara was fired. A source tells NY1 he signed off on the decision to end the case before he was dismissed.