Randy Mastro, a Gibson, Dunn & Crutcher partner and former New York City deputy mayor, has been hired to advise New Jersey Gov. Chris Christie in connection with the ongoing fallout from last fall’s closing of toll lanes leading to the George Washington Bridge.

Christie’s office announced Thursday that Mastro will lead a Gibson Dunn team hired to assist with an internal review of the events surrounding the four-day traffic snarl that plagued suburban Fort Lee as a result of the lane closings. Since the simmering controversy erupted into a full-blown scandal last week with the release of hundreds of pages of documents related to the bridge incident, four people close to the Republican governor have either resigned or been fired amid revelations that they may have taken part in a scheme to deliberately shut the lanes down to punish Fort Lee’s Democratic mayor.