Judge blocks subpoenas in Fed Chair Jerome Powell probe citing 'essentially zero evidence'

A top federal judge in Washington on Friday blocked Justice Department subpoenas to the Federal Reserve's Board of Governors after determining the government "produced essentially zero evidence" to support a criminal investigation of Fed Chair Jerome Powell, according to an unsealed court opinion.

"There is abundant evidence that the subpoenas' dominant (if not sole) purpose is to harass and pressure Powell either to yield to the President or to resign and make way for a Fed Chair who will," U.S. District Judge James Boasberg said in his opinion.

"A mountain of evidence suggests that the Government served these subpoenas on the Board to pressure its Chair into voting for lower interest rates or resigning. On the other side of the scale, the Government has produced essentially zero evidence to suspect Chair Powell of a crime; indeed, its justifications are so thin and unsubstantiated that the Court can only conclude that they are pretextual," the judge added.

Acting U.S. Attorney Jeanine Pirro blasted Boasberg as an "activist" judge and has pledged to appeal his ruling.

"This is the antithesis of American justice -- exonerating anyone without any records, without an investigation or questioning is not how our criminal justice system works," Pirro said in a news conference.

The Justice Department's probe centered on Powell's testimony to Congress last year about cost overruns in a multi-billion-dollar office renovation project.

A spokesperson for the Federal Reserve Bank declined to comment on the ruling.

Powell rebuked the investigation in a video message in January as a politically motivated effort to influence the Fed's interest rate policy.

The Justice Department's move was met with heavy criticism from the Hill especially from key Republicans who stressed the importance of the Fed's independence.

Pirro denied that politics played any role in her probe of Powell and the focus was whether public money has been wasted as a result of the Fed's renovations, and potential false statements to Congress by Powell about the operations.

Sen. Thom Tillis, a North Carolina Republican who sits on the Senate Banking Committee, warned Pirro's office against appealing Boasberg's ruling.

"This ruling confirms just how weak and frivolous the criminal investigation of Chairman Powell is and it is nothing more than a failed attack on Fed independence. We all know how this is going to end and the D.C. U.S. Attorney's Office should save itself further embarrassment and move on," Tillis said in an X post on Friday.

ABC News' Elizabeth Schulze and Ivan Pereira contributed to this report.