The Department of Justice’s criminal investigation into Federal Reserve Chair Jerome Powell is merely “temporarily paused,” a pair of Democratic senators said in a letter sent to the department Friday and obtained first by CNBC.

“Your announcement leaves the door wide open for you to relaunch the criminal probe against Chair Powell – or future baseless investigations into Powell or other Fed Governors and a future Fed Chair – should it once again become politically expedient for you to do so,” Sens. Elizabeth Warren, D-Mass., and Dick Durbin, D-Il., said in the letter addressed to U.S. Attorney for the District of Columbia Jeanine Pirro.

Pirro said in a statement Friday that the Fed’s inspector general had been asked to investigate cost overruns an ongoing renovation project. Pirro didn’t specify who had made the request. Powell had last year asked the inspector general to look into the issue.

“I have directed my office to close our investigation as the IG undertakes this inquiry,” Pirro said. “Note well, however, that I will not hesitate to restart a criminal investigation should the facts warrant doing so.”

Pirro’s office didn’t immediately respond to a request for comment.