The US Justice Department is dropping its investigation into the Federal Reserve chairman, Jerome Powell, over alleged building cost overruns. US Attorney Jeanine Pirro announced that instead, an internal investigation would be led by the central bank's inspector general. President Donald Trump has criticized the expense of the Fed's building renovations, claiming they are excessively high, and this has added to the tension between him and Powell. As Powell's term nears its end, the Senate is considering Trump's nominee, Kevin Warsh, as his replacement. A key Republican senator has said he will not support Warsh unless the investigation into Powell is dropped. White House spokesman Kush Desai emphasized the need for answers regarding the Fed's financial management, asserting that the inspector general's office is best positioned to handle the inquiry. In a statement, Pirro remarked that she would not hesitate to revive the criminal investigation if warranted. The Federal Reserve has chosen not to comment further on the investigation. As part of the renovations, the Fed is updating buildings that haven't seen significant changes since their construction in the 1930s and are addressing issues like asbestos removal. Powell, initially nominated by Trump in 2017, plans to remain in his role until Warsh’s confirmation by the Senate.