O’Reilly, who was supposed to have the night off, called into his own show to make his controversial comments.
"You have a mayor that comes in, a man named Bill de Blasio. He is a far left individual, who is incompetent," O'Reilly said. "He cannot run the city of New York."
O'Reilly said that the suspect in the murders of the two officers, Ismaaiyl Brinsley, was an evil man accommodated by protestors.
"Everybody should know this is a terrible individual. And I hope he's enjoying hell right now," O'Reilly stated.
"Aiding and abetting Brinsley and other maniacs? Those protesters who yelled 'we want dead cops.' Everybody heard it. Those people should be shunned. If you know them, never speak to them again."
De Blasio, O'Reilly claimed, has been anti-police his entire career.
"Who's his best friend? Al Sharpton. Al Sharpton. A racial provocateur and anti-cop individual is de Blasio's best friend. That says it all."
O'Reilly said cops were right to turn their backs on de Blasio at Woodhull Hospital. "Good for them," he added.
"This is an individual who should resign today," O'Reilly concluded. "He cannot run this city; he's lost the control of the police department, and their respect."
"They will never come back, no matter what he says, because he sided with the protesters ... and he has disgraced the office of Mayor of New York City. He should resign.”