Jared Kushner received emails in September 2016 about WikiLeaks and about a “Russian backdoor overture and dinner invite” and forwarded them to another campaign official, according to a letter to his attorney from the bipartisan leaders of the Senate Judiciary Committee.

Committee Chairman Chuck Grassley (R-Iowa) and ranking member Sen. Dianne Feinstein (D-Calif.) said Kushner failed to turn over the relevant documents when they asked for them last month.

“We appreciate your voluntary cooperation with the Committee’s investigation, but the production appears to have been incomplete,” the pair wrote in a letter dated Thursday to Kushner’s attorney, Abbe Lowell.

In a section of the letter titled “Missing documents,” Grassley and Feinstein said Kushner, President Donald Trump’s son-in-law and a White House senior adviser, had handed over some materials but omitted communications that mentioned some of the people connected to the investigation into Russian meddling in the 2016 election.