The U.S. attorney's manual requires that prosecutors not bring witnesses before a grand jury if there is a possibility of future criminal charges unless the witnesses are notified in advance that their testimony can be used against them in a later indictment.
Rove has already made at least three grand jury appearances and his return at this late stage in the investigation is unusual.
The prosecutor did not give Rove similar warnings before his earlier grand jury appearances.
Rove offered in July to return to the grand jury for additional testimony, and Fitzgerald accepted that offer last Friday after taking grand jury testimony from the formerly jailed New York Times reporter Judith Miller.
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