FORT LEE, N.J. - The chief federal prosecutor in New Jersey says he's now investigating the closure of three lanes on the George Washington Bridge for four days last September amid accusations it was political revenge against the mayor of Fort Lee.

At a press conference this morning, New Jersey Gov. Chris Christie claims he knew nothing about the lane closures and says his deputy chief of staff, Bridget Ann Kelly, lied to him. Christie has since fired her. The governor also apologized, saying he was "stunned" by the actions of his staff.

Critics claim the lane closures that snarled traffic on the bridge were ordered as punishment for the Democratic mayor of Fort Lee, who refused to endorse Christie in his re-election bid last year. Christie says he never asked for an endorsement from the mayor and insists he is not a bully.

Christie also asked Bill Stepien, his former campaign manager, to withdraw his name from consideration as leader of the state's Republican Party.