New Jersey Gov. Chris Christie (R) hired an outside law firm Thursday to help with an internal review of the bridge scandal that has engulfed his administration. 

Christie’s team brought on the firm Gibson, Dunn & Crutcher LLP to help with its own internal review, in addition to assisting with the U.S. attorney’s review of the incident.  

Christie had announced last week he would be conducting an internal review, as he apologized after firing his deputy chief of staff for her involvement in a scheme last year to close down lanes on the George Washington Bridge, in apparent retribution for a Democratic mayor in the area who refused to endorse the governor's reelection bid. 

Christie, a potential contender for president in 2016, has said he had no prior knowledge of his staff's involvement. 

“Governor Christie made clear last week that he will conduct an internal review to uncover the facts surrounding the lane closures in Fort Lee,” his office said in a statement. “His Administration is fully cooperating with the U.S. Attorney inquiry and other appropriate inquiries and requests for information.”

Christie’s office added the law firm “will bring an outside, third-party perspective to the situation, and they will be a valuable asset as we move forward. This Administration is committed to ensuring that what happened here never happens again. That’s what the people of New Jersey deserve.”

Former federal prosecutor Randy Mastro will head Christie’s team. He formerly served as the deputy mayor of New York City and worked as a U.S. assistant attorney in the state. He has a background in organized crime cases.  

Along with Christie’s and the U.S. attorney’s review, the state legislature has formed a special committee to investigate the scandal. It announced Wednesday it would bring on a former prosecutor in the case against former Illinois Gov. Rod Blagojevich (D) to lead the investigation.