Washington (CNN) -- Embattled New Jersey Gov. Chris Christie forcefully stood by his account that he only found out about notorious traffic lane closures at the George Washington Bridge last year after they appeared in the media and that he knew absolutely nothing about a suggested political motive behind them.
"The answer is still the same," Christie said in a radio interview on Monday night, adding later that he can't wait to get the "full story" behind the scandal that has rocked his administration and, for now, has clouded any potential presidential run in 2016.
"The fact of the matter is I've been very clear about this. Before these lanes were closed, I knew nothing about them. I didn't plan it. I didn't authorize it. I didn't approve it. I knew nothing about it," he said in a studio appearance for a live call-in show hosted by New Jersey 101.5.
The fresh response came amid a new allegation from a former top adviser caught up in the scandal, David Wildstein, that "evidence exists" that Christie knew about the closures and resulting traffic gridlock over five days in Fort Lee in real time, which would, if true, contradict his account of events.
On CNN's "Piers Morgan Live" Fort Lee Mayor Mark Sokolich said he believed Christie but thought the governor should sign a sworn statement backing up his claims.
"I take it him at his word but it would appear from the polls that a lot of folks don't," Sokolich said.
Why is this important?
Christie's recollection ultimately may be critical in answering why the bridge lanes overseen by the Port Authority of New York and New Jersey were closed in the first place and who authorized it for sure -- and whether any laws were broken.
E-mails and political figures in New Jersey have suggested the gridlock was a bit of orchestrated political payback for the Fort Lee mayor, who did not endorse Christie for re-election last November.
A state legislative committee is investigating as is the Justice Department, which would be interested if there was any abuse of power. Both have subpoenaed Christie's office for documents, and he said his office is complying. Christie's office also has hired a private law firm to investigate.
And why is Wildstein important?
It has been suggested in the e-mails released by state legislative investigators in New Jersey that Wildstein, a top Christie appointee at the Port Authority, carried out the closures. He also has been subpoenaed, refused to answer questions from legislative investigators, and he's got a lawyer.
For his part, Christie has fired a top aide linked to what has metastasized into a political scandal coming on the heels of a successful re-election and prior to a possible White House bid. Others have left their jobs as the scandal unfolded, including Wildstein.
Former deputy chief of staff Bridget Ann Kelly, whose e-mail to Wildstein -- "Time for some traffic problems in Fort Lee" -- weeks before the gridlock occurred led to her firing by Christie in January, refused on Monday on constitutional grounds to comply with a state legislative subpoena to turn over documents, a source with knowledge of the matter told CNN's Chris Frates.
State lawmakers leading that investigation said they are reviewing the matter and "considering our legal options with respect to enforcing the subpoena."
Christie, in the radio interview, repeated what he said at a January news conference -- challenged by Wildstein in a letter written by his lawyer to the Port Authority on Friday -- about the timeline around when he became aware of the traffic mess. He also denied having any knowledge of a suggested political motive.
"The first time that this really came into my consciousness, as an issue" was when an e-mail from Port Authority Executive Director Pat Foye "was leaked to the media and reported on."
Foye was the person, according to e-mails, who started asking questions about the lane closures and ordered them reopened.
That's when Christie said he asked his chief of staff and his chief counsel to "look into this and see what's going on here."
He said any reference to the bridge situation prior to this wouldn't have meant anything to him because he wasn't clued into the fact that there was a problem.
Afterward, Christie said again that he was told the "Port Authority was engaged in a traffic study," which has now been called into serious question.
He also stressed that "nobody has said I knew anything about this before it happened, and I think that's the most important question."
A question of evidence
Christie's appearance follows steps by his office over the weekend to strike in an unusually personal way against Wildstein, a one-time high school classmate of the governor in Livingston, N.J.
"Bottom line - David Wildstein will do and say anything to save David Wildstein," a letter released by the governor's office said in a statement.
On Monday, Christie's office also planned to send to friends and allies a list of tweets and stories aiming to put the focus on The New York Times' handling of the disclosure by Wildstein, according to CNN's Jake Tapper.
The Times broke the story, saying Wildstein "had the evidence to prove" Christie knew about the lane closures. The newspaper quickly revised its lead to simply reflect what the letter written by Wildstein's attorney actually said: that "evidence exists," not that Wildstein was in possession of it.
The letter never disclosed the evidence.
The letter also didn't suggest that Christie had knowledge of what his people might have been up to -- political or otherwise.
The scandal and another allegation of strong-arm political tactics by Christie administration officials over Superstorm Sandy aid have generated a wave of negative political fallout for a governor overwhelmingly re-elected in November and considered a top-tier Republican presidential hopeful in 2016.
Christie's swagger and straight-shooting style had him riding high in the polls as late as December.
He topped other potential GOP 2016 White House hopefuls in various surveys. But those numbers have faded as the scandal has intensified, according to a new CNN/ORC International survey.
Christie trails Hillary Clinton by 16 percentage points in a hypothetical presidential match-up, a turnaround from December when he was up by 2 points.
CNN's Cassie Spodak, Paul Steinhauser, and Chris Frates contributed to this report.