"Given that Senator Obama was a long time friend to Tony Rezko's he should be asked to release their documents from their side of the transaction," Fitzgerald said. He noted the closing statements and other mortgage documents "would show the flow of funds from his standpoint on the transaction."
Rezko is currently in prison awaiting sentencing for his attempts to corrupt politicians in Illinois.
Obama has described his decision to purchase land at a discount from Rezko as "boneheaded" in the past.
Fitzgerald's request came hours after the American Conservative Union filed an ethics complaint to the U.S Senate over the same deal.