"I think we are clearly there with the results of the special-counsel team," he told CNN host Chris Cuomo on Thursday. "There are so many witnesses who could provide important essential testimony to Congress that can only be done in the scope of an impeachment inquiry."
McCabe, whom then-Attorney General Jeff Sessions fired from the FBI in March 2018, made those comments as a small portion of House Democrats called for President Trump's impeachment and Speaker Nancy Pelosi, D-Calif., pushed back on the idea.
Pelosi has said that if impeachment failed, it might hurt Democrats' prospects of prosecuting him after he left office. However, McCabe said an inquiry was warranted even if it didn't result in articles of impeachment or removal by the Senate.
"I think the American people have a right to hear from the witnesses and understand exactly what actions the president engaged in, and they have the opportunity to factor that information into their decisions, their voting decisions, whatever that might be going forward," he said.
McCabe told CNN last February he thought it was "possible" Trump was a Russian asset. He's also pushed back the Republicans' narrative that Mueller's report showed Trump didn't commit any crimes.
"What has been billed as 'no collusion, no obstruction' should probably be recast as 'no witch hunt' and 'no exoneration,'" he told MSNBC in May. Mueller's report did not conclude either obstruction or conspiracy occurred but did raise a number of issues that provoked concerns from the left wing.