Unlike much of the trial testimony so far, Hannon's account tied Rezko directly to a major component of the corruption that prosecutors say was swirling around state boards and commissions three and four years ago.
Rezko, 52, is charged with scheming with attorney Stuart Levine to split a $1.5 million bribe from a contractor for a favorable vote on a hospital project and squeeze money management firms for kickbacks in exchange for business from a state pension board.
Prosecutors say Rezko parlayed the influence he gained as a fundraiser for Gov. Rod Blagojevich into the clout he need to make the plan work.
Rezko denies having anything to do with such a scheme. Levine has pleaded guilty to his role in the scheme and testified for the government. Blagojevich has not been accused of wrongdoing.
Hannon testified that Rezko had long owed him and his wife, Fortunee Massuda, millions of dollars. He said Massuda had borrowed the money from banks and turned it over to Rezko.
He said Rezko made various proposals to repay the money, and during one conversation said Massuda might be set up to get a finder's fee if Blagojevich went through with a plan to lease or sell the Thompson Center.
But Massuda had no interest in such a plan, Hannon testified.
The plan to sell the Thompson Center was floated early in the Blagojevich administration but fizzled.
Rezko has been in federal custody since Jan. 28, when U.S. District Judge Amy J. St. Eve revoked his bond, saying a $3.5 million wire transfer he received from a London-based billionaire after claiming he was broke suggested that he might flee before the start of the trial.
Rezko's lawyers announced Thursday morning, though, that they are making a fresh effort to get him out on bond. St. Eve said she wanted to give federal prosecutors a chance to reply to the motion before deciding.The Associated Press contributed to this report.