White House on edge as Mueller quietly pursues Russia probe

For two months, Robert Mueller -- the lanky, 72-year-old independent prosecutor investigating the Russia scandal -- has worked in virtual silence in a nondescript government office building in downtown Washington.Mueller has built a team of more than a dozen tough-as-nails investigators, including one expert in flipping mafia witnesses, a money laundering specialist who chased down a corrupt billionaire, and one of the country's most experienced Supreme Court litigators.