A US judge has ruled a congressional committee investigating the Capitol riot can access some of ex-President Donald Trump’s White House records.
Mr Trump had sought to invoke executive privilege, under which presidential documents can be kept secret.
The inquiry is trying to find out if Mr Trump had prior knowledge of the riot.
Trump supporters stormed the Capitol building on 6 January as Congress was certifying President Joe Biden’s election victory.
Mr Trump has refused to acknowledge losing the election last year, claiming – without evidence – that it had been rigged.
The inquiry is being conducted by a committee set up by the House of Representatives which is dominated by President Biden’s Democrats.
The panel wants to see a trove of phone records, visitor logs and other White House documents that could shed some light on the events leading up to the attack on Congress.
It has issued summonses to several Trump aides to testify before the lawmakers.
Mr Trump – a Republican – had argued his White House communications were protected and as such should not be released.
But US District Judge Tanya Chutkan ruled that the National Archives, the federal agency that holds the records, should comply with the panel’s request.
In a 39-page ruling, Judge Chutkan said that Congress had the right to see the documents, particularly as the current president had agreed.
Mr Trump “does not acknowledge the deference owed to the incumbent president’s judgment. His position that he may override the express will of the executive branch appears to be premised on the notion that his executive power ‘exists in perpetuity,'” the judge wrote. “But presidents are not kings, and the plaintiff is not the President.