Jared Kushner’s lawyer failed to give the US Senate Judiciary Committee documents President Donald Trump’s son-in-law and senior adviser received about a”Russian backdoor overture and dinner invite,” the committee’s leaders said on Thursday.

In a letter to Kushner’s attorney, Abbe Lowell, Senators Chuck Grassley and Dianne Feinstein, the Judiciary Committee’s Republican chairperson and top Democrat, listed the documents and emails among materials Lowell has failed to produce.

Kushner, the letter said, also forwarded to an unidentified campaign adviser emails from September 2016 concerning Wikileaks, the whistleblower group that published emails US intelligence agencies determined Russian military intelligence had hacked from Democratic Party accounts.

“It appears that your search may have overlooked several documents,” the letter said of Lowell’s responses to three requests for materials related to the committee’s investigation on Russian interference in the 2016 presidential election.

“Mr. Kushner and we have been responsive to all requests,” Lowell said in a statement. “We provided the Judiciary Committee with all relevant documents that had to do with Mr. Kushner’s calls, contacts or meetings with Russians during the campaign and transition, which was the request. We also informed the committee we will be open to responding to any additional requests and that we will continue to work with White House Counsel for any responsive documents from after the inauguration.”

When asked about the letter, White House press secretary Sarah Huckabee Sanders referred reporters to Lowell. Trump denies any collusion between his campaign and Moscow.

Russia denies a January report by three US intelligence agencies that it conducted an influence operation to skew the 2016 presidential vote in favor of Trump over his Democratic rival, Hillary Clinton.