I have no recollection

Typically invoked by governmental officials during sworn testimony to the U.S. Congress to deny potentially damaging -- politically and/or criminally -- behavior.

From the 1994 film "Clear and Present Danger" starring Harrison Ford:

Jack Ryan: Who authorized this?
Robert Ritter: I'm sure they'll ask you that.
Jack Ryan: Who authorized it?
Robert Ritter: I have no recollection, Senator