Both men spoke of using Russian diplomatic locations for this very purpose.
Mr. Kislyak told Russian officials of Mr. Kushner’s unusual request in early December. Former National Security Adviser Mike Flynn also attended this meeting.
The U.S. intelligence intercepted these communications from Mr. Kislyak at the time.
The intelligence community closely follows Russian officials domestically and internationally. The FBI follows Russia activities in the U.S. and the N.S.A. follows Russia’s activity abroad.
Anyone who enters or exits a Russian Embassy in the United States is known to the FBI.
A former senior intelligence said Mr. Kushner “seems extremely naive or absolutely crazy,” according to the Washington Post.