Exclusive: Secret witness in Senate Clinton probe is ex-lobbyist for Russian firm

The Senate committee searching for Clinton's alleged wrongdoing is keeping their witness's name cloaked. However, William D. Campbell, a lobbyist, confirmed to Reuters he is the informant who will testify and provide documents to Congress about the Obama Administration’s 2010 approval of the sale of Uranium One, a Canadian company with uranium mines in the United States, to Russia's Rosatom.