REVEALED: The FBI opened a secret investigation into whether Trump worked for Russia

The FBI in 2017 opened a secret probe into whether Donald Trump was working for Russia when he fired former director James Comey early in his presidency, the New York Times reported Friday evening.

Former law enforcement officials told the Times that agents and more senior FBI officials were suspicious of Trump's ties to Russia during his 2016 campaign -- but held off " in part because they were uncertain how to proceed with an inquiry of such sensitivity and magnitude."

An investigation was opened in the days following Comey's firing and including a now-well-known criminal aspect, the report noted: whether Trump obstructed justice in doing so.

"Counterintelligence investigators had to consider whether the president’s own actions constituted a possible threat to national security," the report noted. "Agents also sought to determine whether Mr. Trump was knowingly working for Russia or had unwittingly fallen under Moscow’s influence."