Jessica Mendoza

The Justice Department's investigation into Jerome Powell centers around a building, the Federal Reserve's headquarters in Washington, D.C.,

The building has been under renovation for years, and construction costs have ballooned over budget by hundreds of millions of dollars.

Back in June, Powell was called to testify about the renovation in front of the Senate Banking Committee.

The Fed says the project has faced cost overruns, in part because of unforeseen construction conditions, including more asbestos than expected and toxic contamination in the soil.

After Powell testified in June, White House Budget Director Russell Vogt sent him a letter.

It said that Powell's testimony was at odds with the public plans for the building.

Powell responded by defending his testimony to Congress.

But the scrutiny over the renovations tracked with a broader critique of Powell's leadership.

Some in the White House pointed to the cost overruns as an example of the Fed chair's incompetence.

President Trump has also publicly complained that Powell was taking too long to lower interest rates.

The Fed hadn't adjusted interest rates since the start of Trump's second term, mainly because it was concerned about the risk of inflation that could be brought on by Trump's tariff policy.

Still, Trump repeatedly called for Powell to be ousted, saying he wants to replace him before Powell's term expires in May.

This past July, the tension between the two men was on full display.

Powell and Trump, accompanied by members of the press, took a tour of the Federal Reserve construction site.

The tour was awkward.

At one point, Trump claimed that the renovation's price tag had swelled to $3.1 billion.

A few months later, the Fed did decide to cut interest rates.

Inflation hadn't spiked because of the tariffs.

Plus, there were new concerns about a weakening job market.

So these renovations were at issue over the summer.