For the first time in their probe of alleged corruption in Chicago city government, federal investigators today questioned Mayor Richard Daley. Daley disclosed the interview at a City Hall news conference but would not say what he was asked. He refused to answer whether the meeting specifically concerned the city's scandal-plagued Hired Truck Program. "What I can say is I answered their questions fully and openly," Daley said. "I cannot comment on the substance of their questions." Representatives of the U.S. attorney's office in Chicago spoke with the mayor for two hours, city officials said. City Corporation Counsel Mara Georges...