The campaign fund investigation of U.S. Rep. Jesse Jackson Jr. has expanded to include his wife Sandi, two people familiar with the case said. The two told the Wall Street Journal federal prosecutors are reviewing evidence suggesting Sandi Jackson was complicit in misusing campaign funds to decorate the couple\'s Washington home. Congressman Jackson, who represents Chicago and some of its southern suburbs, is currently at the Mayo Clinic in Minnesota being treated for bipolar disorder, his aides said. His wife is a member of the Chicago City Council representing the 7th Ward. Prosecutors could use the threat of charging Sandi Jackson to extract a guilty plea from the congressman, a Washington attorney said. Barry Pollack, who is not connected to the case, said political spouses often become key players in corruption investigations.