Jared Kushner has been accused of failing to disclose emails he received about possible Russian collusion with Donald Trump's presidential election campaign team in 2016.
According to two senators, who are part of an investigation into alleged Russian involvement, Mr Kusher provided an “incomplete” disclosure of files to their committee.
Mr Kushner, who is married to Mr Trump's daughter Ivanka and is a close adviser to the President, helped run Mr Trump's digital media strategy in last year's campaign
In a letter, the senators - Senator Charles Grassley, a Republican, and Senator Diane Feinstein, a Democrat - said they knew about a string of emails that were relevant to inquiries, but were not included in the disclosure.
Abbe Lowell, Mr Kushner’s lawyer, said his client had 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."
Ms Feinstein and Mr Grassley claim Mr Kushner received emails concerning a "Russia back door overture and dinner invite".
The senators have also asked for communications between Mr Kushner and ex-national security adviser Michael Flynn.
Mr Flynn was forced to resign in February after he lied to Vice-President Mike Pence about a meeting with a Russian envoy.