Jared Kushner has failed to turn over documents to the Senate Judiciary Committee, according to a letter from committee chair Sen. Chuck Grassley Nov. 16.
The letter, also signed by ranking Democrat Sen. Dianne Feinstein, stated that Kushner received emails about WikiLeaks in September 2016 and an email from unspecified Russians trying to set up a backdoor contact, The Washington Post reported.
The nature of the back channel was not clear, The New York Times reported.
Kushner's attorney, Abbe Lowell, originally received a request for the documents in October.
"We appreciate your voluntary cooperation with the investigation, but the production appears to have been incomplete," Grassley and Feinstein noted, according to Politico.
The committee has been investigating President Trump's alleged ties to Russia and Trump's firing of FBI Director James Comey.
Kushner is President Donald Trump's son-in-law and a senior adviser to the commander-in-chief.
The two senators informed Lowell that documents mentioning Kushner were obtained from other sources.
"If, as you suggest, Mr. Kushner was unaware of, for example, any attempts at Russian interference in the 2016 presidential election, then presumably there would be few communications concerning many of the persons identified," added Grassley and Feinstein.
The committee appealed for other communications data.
"You also have not produced any phone records that we presume exist and would relate to Mr. Kushner's communications," Grassley and Feinstein added to Lowell, according to the Post.
In addition, the Senate committee wants to see any communication between Kushner and former National Security Adviser Michael Flynn. Documents referring to email hacking, the Magnitsky Act and Russia were requested, as well as all communication between Flynn and Kushner since the 2016 election.
The Judiciary Committee is also seeking a copy of Kushner's interview with the Senate Intelligence Committee to determine "whether the transcript satisfies the needs of our investigation."
The letter urged Kushner's attorney to produce the documents by Nov. 27.
The request comes after it was revealed that Donald Trump Jr., Trump's eldest son, exchanged private messages with the WikiLeaks account on Twitter during the 2016 campaign.
Lowell responded to the Senate Judiciary Committee in a Nov. 16 statement.
"We provided the Judiciary Committee with all relevant documents that had to do with Mr. Kushner's calls, contacts or meetings with Russia during the campaign and transition, which was the request," Lowell stated, according to the Times. "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."
Sources: The Washington Post via Chicago Tribune, Politico, The New York Times / Featured Image: Gage Skidmore/Flickr via Wikimedia Commons / Embedded Images: Shealah Craighead/The White House/Flickr via Wikimedia Commons, U.S. Department of State/Flickr via Wikimedia Commons