Former acting FBI director Andrew McCabe said on Tuesday that he believes it’s possible President Donald Trump is a Russian “asset.”

Anderson Cooper asked his guest, “Do you still believe the President could be a Russian asset?” McCabe replied by expressing his belief that it’s plausible he is. “I think it’s possible. I think that’s why we started our investigation, and I’m really anxious to see where [special counsel Robert] Mueller concludes that,” McCabe said.

During their conversation, McCabe also admitted he opened his own investigation into whether Trump was working to further Russia’s agenda. He said Trump was undermining institutions he should be working with. “This President is undermining the role of law enforcement, undermining the role of our intelligence infrastructure and negatively impacting the men and women of the FBI, and across the intelligence agencies, (and their) ability to protect this country on a daily basis,” he said.

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McCabe is currently on tour promoting his new book, The Threat: How the FBI Protects America in the Age of Terror and Trump. It details his time working in the bureau under Trump, covering his conversations with White House and Justice Department officials. McCabe became the acting FBI director after Trump fired James Comey in May 2017, and he was frequently ridiculed publicly and was fired two days before his retirement date.

White House supervisor Kellyanne Conway fired back at McCabe’s comments speaking on CNN’s Cuomo Prime Time, calling him a “liar and a leaker.” Trump also enjoys taking shots at McCabe, most recently calling him “a puppet” in the Russian collusion narrative Comey allegedly constructed.