President Trump called CIA officer Eric Ciaramella “a radical” in response to reports that he may be the whistleblower who filed a complaint about his July 25 phone call with Ukraine and sparked House impeachment proceedings.

Ciaramella was listed as the potential whistleblower in a report published Wednesday by RealClearInvestigations. He worked under several prominent Democrats, including Joe Biden, John Brennan, and Susan Rice during the Obama administration. Many have questioned Ciaramella’s political bias, although he has not been confirmed to be the whistleblower.

During a press gaggle on Sunday, Trump said he doesn’t know if Ciaramella is the whistleblower but called him a radical.

“Well, I’ll tell you what. There have been stories written about a certain individual, a male, and they say he’s the whistleblower,” Trump said. “If he’s the whistleblower, he has no credibility because he’s a Brennan guy, he’s a Susan Rice guy, he’s an Obama guy.”

He added, “And he hates Trump. And he’s a radical. Now, maybe it’s not him. But if it’s him, you guys ought to release the information.”

The whistleblower’s attorneys have been working to protect their client’s identity, refusing to confirm or deny reports naming Ciaramella. They called attempts to identify the whistleblower the “pinnacle of irresponsibility.”