Rezko, 52, is charged with scheming with Levine to pressure firms seeking state business for kickbacks and split a $1 million bribe from a contractor who wanted to build a hospital in north suburban Crystal Lake.
Rezko denies he ever took part in such a scheme. But the 62-year-old Levine has pleaded guilty and is on the stand as the government's star witness in hopes of getting a lenient sentence.
Levine was a member of both the health facilities board and another board that decided which money management firms got allocations from the $40 billion fund that pays retired teachers' pensions.
Duffy's questions Thursday were designed to suggest Rezko did not order Thomas Beck, then the chairman of the health facilities board, to push approval of the Crystal Lake project through the board.
Levine acknowledged FBI tapes of phone conversations in which Beck repeatedly said he did not want even to bring up the Crystal Lake proposal at the April board meeting because it was too badly flawed.
But Levine said that at some point in the two days before the board met, Beck had obviously spoken with Rezko and done an about-face. Levine said he remembered seeing somewhere the transcript of a phone conversation between himself and Beck in which Beck said that his position had changed.
Duffy challenged him to name any conversation in which Beck had made such a statement to him and they spent more than an hour going through transcripts of FBI wiretap tapes, trying to find the call in question.
But such a transcript didn't turn up and prosecutors sat by silently as the search went on.
Levine has testified that he believes he would have been sent to federal prison for the rest of his life if he had fought the charges against him. He has pleaded guilty and taken the stand as the government's star witness in hopes of getting a lenient 5 1/2-year sentence as a reward.
On Thursday, he seemed to be struggling to make the transcripts that do exist match his testimony that Rezko had ordered Beck to approve the Crystal Lake project.
At one point, he directed attention to a phone conversation between himself and the contractor who was to build the hospital once board approval was secured.
"We're fine," he is heard telling the contractor, Jacob Kieferbaum. He said that represented his assurance of a favorable vote by the board.
"That is an obvious statement that Mr. Kieferbaum understood and I understood," Levine insisted. But Duffy scoffed at that answer.
"I'm not interested in your interpretation," he said.
The Associated Press contributed to this report.