Prosecutors on Tuesday dropped all charges against U.S. hip-hop drama Empire actor Jussie Smollett, who was accused by Chicago police of staging a hate crime attack on himself.

The astonishing twist triggered controversy immediately, and Chicago mayor angrily termed the development as "a whitewash of justice."

Smollett, 36, an African American and open gay actor, allegedly paid two brothers he knew 3,500 U.S. dollars to stage an attack on himself in downtown Chicago on the early morning of Jan. 29.

Upon the attack report by himself, Chicago police first treated the high profile case as a possible hate crime. However, as investigation deepened, according to Chicago police, they found evidence indicating the actor orchestrated the attack because he was dissatisfied with his salary on the Empire.

On Feb. 21, Smollett surrendered to Chicago police after local prosecutors approved felony charges of disorderly conduct for allegedly making false police report.

However, on Tuesday morning, prosecutors in Cook County, Illinois, issued a statement following a surprise court hearing.

"After reviewing all of the facts and circumstances of the case, including Mr. Smollett's volunteer service in the community and agreement to forfeit his bond to the City of Chicago, we believe this outcome is a just disposition and appropriate resolution to this case," said the statement.

Prosecutors did not explain in detail why they decided to drop all the charges.

Mayor Rahm Emanuel, standing by Chicago police chief Eddie Johnson at a press conference in the afternoon, blasted the prosecutors' decision and emphasized that a grand jury had chosen to bring 16 counts of disorderly conduct against Smollett.

"This is, without a doubt, a whitewash of justice and sends a clear message that if you're in a position of influence and power, you get treated one way, other people will be treated another way," said the mayor.

"There is no accountability then in the system. It is wrong," he added.

Johnson said he still stands behind the detectives' investigation and accused Smollett and his legal team of bypassing due process of law.

But Smollett's attorneys insisted that their client had been "vilified," accusing Chicago police of "proving a case in the court of public opinion."