One of Chicago's most powerful labor unions, once run by the son-in-law of a top mobster, "continues to be infiltrated by organized crime," a union hearing officer ruled this week in a move that could lead to a purge of the leadership. "This will hurt the mob big time," said former FBI agent Jack O'Rourke, an organized crime expert who investigated Laborers Local 1001, which represents hundreds of city employees, many Streets and Sanitation workers. It's "been influenced by the mob for 50 years." But alleged mob influence wasn't the only reason hearing officer Peter Vaira ordered the 2,800-member local...