The letter from David Wildstein's lawyer said evidence exists suggesting the governor knew about the closures as they happened in September - which, if accurate, contradicts some statements Christie made on the matter. The letter, though, does not detail any evidence.
Attorney Alan Zegas' letter focuses on a nearly two-hour televised news conference Christie gave on Jan. 9 where his responses to questions about what he knew about the closures and when could be open to interpretation. But at a Dec. 13 news conference, the Republican governor said definitively he didn't know about the traffic problems until they were over.
Asked about the traffic backups, Christie noted a top leader at the Port Authority of New York and New Jersey, the entity that runs the bridge, was slow to learn of the closures so it's no surprise Christie wouldn't hear about them until later.
"It was certainly well after the whole thing was over before I heard about it," Christie said.
The Republican governor's office said the letter's claim does not contradict Christie's statements.
"He had absolutely no prior knowledge of the lane closures before they happened and whatever Mr. Wildstein's motivations were for closing them to begin with," Christie's office said in a statement. "As he said in his Jan. 9 press conference, (he) had no indication that this was anything other than a traffic study until he read otherwise the morning of Jan. 8."
When asked directly about what Christie said on Dec. 13, the governor's office reiterated its statement.
The unannounced lane closures caused massive gridlock in Fort Lee in September, delaying emergency vehicles and school buses and tying up some commuters for hours over four mornings.
New Jersey legislators are investigating whether Christie aides engineered the lane closures to send a message to the town's Democratic mayor. Twenty subpoenas for documents and correspondence related to the lane closings are due to be returned to the legislative panel on Monday. The U.S. Attorney's office is also investigating.
Christie, who has been seen as a possible 2016 presidential contender, could be vulnerable because of the scandal. At the very least, it gives opponents something to criticize, and it could tarnish the image he has built as a pragmatic conservative who is willing to work with Democrats on key issues.
At the nearly two-hour news conference on Jan. 9, Christie's statements did not necessarily address when he learned of the closings, however he flatly denied knowing anything about an apparently political motive until months later.
When asked if he understood why people would have a hard time believing "you didn't know about this thing," he responded:
"I don't know what else to say except to tell them that I had no knowledge of this - of the planning, the execution or anything about it - and that I first found out about it after it was over."
"And even then, what I was told was that it was a traffic study," he said.
In another instance, asked if he had authorized the retribution, Christie said: "Oh, absolutely not. No. And I knew nothing about this. And until it started to be reported in the papers about the closure, but even then I was told this was a traffic study."
On Friday night, Christie appeared at a birthday party for radio personality Howard Stern, but did not take questions after introducing a performance by Jon Bon Jovi. Christie is scheduled to attend a Times Square event Saturday to hand off the Super Bowl to next year's hosts in Arizona. He and his family are planning to watch the Super Bowl from a luxury box on Sunday.
Zegas' letter to the Port Authority requests that the agency pay Wildstein's legal bills. Wildstein was Christie's No. 2 man at the Port Authority before resigning in December.
In the letter, Zegas said his client "contests the accuracy of various statements that the governor made about him and he can prove the inaccuracy of some."
At his Jan. 9 news conference, Christie said Wildstein clearly "played a major role" in the closures but said he had no contact with him for "a long time, a long time."
"I could probably count on one hand the number of conversations I've had with David since he worked at the Port Authority," Christie said. "I did not interact with David."
The letter does not say what the evidence is and is unclear about whether Wildstein is suggesting he has material that has not been made public previously or whether he is referring to information that has been reported in recent weeks. Zegas did not return calls from The Associated Press.
Wildstein, who attended Livingston High School with Christie, supplied hundreds of pages of documents, some heavily redacted, to the legislative committee investigating at the time. He also appeared under subpoena on the same day as Christie's Jan. 9 news conference, but refused to answer any questions about the lane closures.
He even refused to say whether he had previously worked at the Port Authority, though just weeks earlier, he publicly resigned from his post there.
Wildstein, who previously was a political blogger, said Zegas advised him to remain silent for fear of being prosecuted. Zegas has said Wildstein would be willing to talk if granted immunity from criminal investigators.
The committee found him to be in contempt and referred the case to a prosecutor.
Christie had adamantly denied staff members were involved until private emails that were subpoenaed and released showed otherwise. Besides Wildstein, three others connected to Christie have been fired or resigned.
No subpoenas target Christie himself, who has just begun a yearlong chairmanship of the Republican Governors Association.
Leaders of the legislative panel investigating the matter said Friday that they would consider the letter from Zegas as part of their probe. They also said they were reviewing their legal options after receiving a letter from the lawyer for Christie's former campaign manager, Bill Stepien, who is fighting a subpoena and said he would not comply with the committee because federal prosecutors are also looking at the case.
Some Democrats pounced on Friday's letter from Wildstein's lawyer. Milly Silva, a union executive who ran for lieutenant governor last year, issued a statement saying, "If these allegations are proven, it raises serious questions about how New Jersey can continue to move forward under Gov. Christie's leadership.