Per records, powerful congressman offered to quit, then fought allegations ### Mayor Richard M. Daley, right, and U.S. Rep. Dan Rostenkowski attend a news conference together in 1993. Daley praised the longtime congressman after his death last August. ************* The theft of just $7,000 by a stamp clerk in the U.S. House Post Office mushroomed into a federal investigation that brought down one of the most powerful congressmen in the country, the late Daniel Rostenkowski of Chicago, according to records released Thursday by the FBI. The documents reveal that the FBI in 1992 was told by a "reliable source" that...