On July 25, 2016, the Washington Post will report that the FBI warns the “Clinton campaign and dozens of lawmakers” that they are being targeted by hackers. Later reporting by Yahoo News will indicate that the Clinton campaign is first warned by the FBI in March 2016. The timing of the warning to lawmakers is less clear, except that the Post mentions it takes place “weeks before” a media report on June 14, 2016 that hackers had broken into the Democratic National Committee (DNC) computer network.
It still has not been proven that hack on the lawmakers have been successful. However, former Senate majority leader Tom Daschle (D) has told the Post that his email account was hacked recently. But he hasn’t been given any indication if law enforcement is investigating or who the hacker might be. (The Washington Post, 7/25/2016)