WASHINGTON – Rep. Tom Tancredo's charge that Mexican drug cartels are buying up legitimate businesses in U.S. cities to launder money and using some of the proceeds to win local mayoral and city council seats for politicians who can shape the policies and personnel decisions of their police forces, has been backed up by a veteran gang investigator. Richard Valdemar, a retired sergeant with the L.A. County sheriff's department and a longtime member of a federal task force investigating gang activity, went beyond the charges made by Tancredo, the chairman of the House Immigration Reform Caucus who has led the...