The U.S. Department of Justice has ended its criminal investigation into Jerome Powell, concluding a months-long probe tied to cost overruns in renovation work at the Federal Reserve’s headquarters.

U.S. Attorney for the District of Columbia Jeannine Pirro said the matter will now be reviewed by the Federal Reserve’s inspector general, who has been asked to examine the multibillion-dollar construction expenses and provide a comprehensive report.

Pirro said her office is closing the case as the inspector general assumes responsibility for evaluating the issue, but noted the possibility of reopening a criminal inquiry if new evidence emerges.

The investigation had struggled to advance, with prosecutors acknowledging earlier this year that they had not identified evidence of criminal wrongdoing. A federal judge, James Boasberg, dismissed subpoenas issued during the probe, citing insufficient justification and a lack of supporting evidence.

The case had centered on scrutiny of renovation costs at Federal Reserve facilities, though officials did not ultimately establish grounds for criminal charges.

The decision effectively removes a layer of legal uncertainty surrounding Powell’s tenure as chair of the Federal Reserve. It also comes amid discussions about potential leadership changes, with former Fed official Kevin Warsh viewed as a possible successor.

The Federal Reserve’s inspector general is expected to continue reviewing the project’s finances and management practices, focusing on accountability and oversight of taxpayer-funded expenditures.

No timeline has been provided for the completion of that review.