U.S. Attorney Patrick Fitzgerald has filed a motion seeking a 90-day extension to return an indictment against the governor of Illinois.
Federal prosecutors normally have 30 days to file an indictment against a defendant. That deadline would have been Jan. 7, and the extension would give prosecutors until April 7 instead.
Authorities arrested Gov. Rod Blagojevich on Dec. 9 on corruption charges that accuse him of trying to sell President-elect Barack Obama's vacant Senate seat to the highest bidder.
Blagojevich has denied any wrongdoing.
In the motion filed Wednesday, prosecutors ask for more time because "multiple witnesses" have come forward in recent weeks and investigators have to review "thousands of intercepted phone calls."