A more-than-yearlong effort by New Jersey lawmakers to determine who was ultimately responsible for the September 2013 lane closures at the George Washington Bridge - and why they happened - has not yielded evidence that Gov. Christie knew of or was involved in the closures.

And that won't change as long as the legislative committee investigating the incident is unable to interview certain witnesses amid an ongoing investigation by the U.S. Attorney's Office, according to an interim report from the panel that stops short of clearing the governor.

The 136-page report, obtained by The Inquirer late Thursday, shows that the committee also has not determined why access lanes to the bridge were closed without public notice - snarling traffic in Fort Lee over four days. It does identify the closures as the work of the same two former Christie allies who were blamed by a law firm hired by the Republican governor to investigate the incident.

Christie, a potential 2016 presidential candidate, has maintained he played no role in the closures. On Friday, his office described the report as "affirming what the governor has said all along" and released a statement from lawyer Randy Mastro, who issued a report in March that said Christie did nothing wrong.

"The committee has finally acknowledged what we reported nine months ago - namely, that there is not a shred of evidence Gov. Christie knew anything about the . . . lane realignment beforehand or that any current member of his staff was involved in that decision," Mastro said.

The committee's chairman, Assemblyman John S. Wisniewski (D., Middlesex), rejected the assertion that the report affirmed Christie's version of events.

"There's no statement in this report that says the governor . . . had no involvement," Wisniewski said. "What it does say is because we have not been able to interview all the people who are relevant to this inquiry, we don't know if he did or didn't."

The committee - which is to meet Monday - did not offer immunity to certain witnesses, to avoid interfering with the U.S. attorney's investigation, Wisniewski said. "We're just on hold at this point," he said.

On Friday evening, New York television station NBC4 reported that at least six federal indictments could be handed down in the case as soon as January, citing "multiple sources familiar with the investigation." The NBC report said former Christie staffers and current and former Port Authority of New York and New Jersey staffers were among those "potentially facing indictment." It did not name any.

Matthew Reilly, a spokesman for the U.S. Attorney's Office in Newark, declined to comment on the report, saying only that "our investigation is continuing."

The report by the legislative committee's counsel, Reid J. Schar of Jenner & Block, describes the closures as "directly implemented" by Bridget Anne Kelly, the now-fired Christie aide who wrote an e-mail in August 2013 calling for "traffic problems in Fort Lee."

It says Kelly worked closely with David Wildstein, a former Port Authority official who replied "Got it" to Kelly's e-mail. He resigned last December, a month before the e-mail exchange came to light.

While the report does not answer why Kelly and Wildstein acted to close the lanes, it says Democratic Fort Lee Mayor Mark Sokolich's failure to endorse Christie's 2013 reelection was "at least a consideration," noting that Kelly called another aide the night before sending the "traffic problems" e-mail to verify that Sokolich would not be endorsing the governor.

The report describes in detail apparent efforts by Christie staffers to secure Sokolich's endorsement. A number of Democratic officials endorsed Christie.

Alan Zegas, a lawyer for Wildstein, declined to comment. Michael Critchley, a lawyer for Kelly, did not respond to an e-mail seeking comment.

The legislative report notes that a Christie staffer testified before the committee that Wildstein said he told the governor about the lane closures while they were underway.

The report says that since the committee had been unable to interview Wildstein, the testimony "leaves open the question" of when Christie first learned of the closures.

Though the report says the committee found "no conclusive evidence" of whether Christie was aware of the closures or involved before or while they were happening, it says that if Kelly and Wildstein acted alone, "they did so with perceived impunity and in an environment . . . in which they felt empowered to act as they did, with little regard for public safety risks or the steadily mounting public frustration."

The report says Bill Stepien, Christie's former campaign manager, and Bill Baroni, a Christie appointee who resigned from the Port Authority last December, knew of concerns about the closures while they were in effect. Neither was interviewed by the committee; nor was David Samson, a Christie appointee who in March resigned as chairman of the Port Authority board.

The report also describes a politicization of the Christie administration office that conducted outreach to mayors while some employees also worked to secure endorsements for the governor from those mayors.

And it notes that administration aides received notice of the lane closures while they were happening and afterward, characterizing the governor's office as having responded "very slowly and passively to mounting indications" of political motives for the incident.

Christie aides said they were told the Port Authority closed access lanes to the bridge as part of a traffic study.

"It is difficult to review this sequence of events without seeing indications that some of the participants may have known or suspected that the traffic study cover story was a fabrication even as they continued to embrace that story publicly," the report says.

The report also suggests that Christie deleted text messages to a top aide, who told the legislative committee that she texted the governor last December about the performance of Port Authority employees as they testified that day before lawmakers about the lane closures.

Regina Egea, now the governor's chief of staff, told the committee she did not recall receiving a reply from Christie. According to the legislative report, phone records indicate Christie initiated the conversation and sent three messages, while Egea sent nine.

In response to a subpoena from the committee, lawyers for the governor's office said they were unable to locate the texts on the phones of Christie or Egea, indicating that both had "deleted the messages at some unknown point," the report says.

Christie has said he does not recall receiving a text from Egea that day.

The legislative report is the result of dozens of subpoenas seeking testimony and records of phone calls and e-mails. The governor's office provided 90,000 pages of documents, three-quarters of which were "non-substantive," the report says.

Much of the information in the report had already been publicly disclosed. But some of the report draws on interviews conducted in private by counsel and unreleased information from subpoenas.

Records show lawyers for the legislative committee billed the state more than $900,000 through the end of July. The firm hired by Christie, Gibson Dunn, billed $7.2 million through the same period.

mhanna@phillynews.com 609-989-8990 @maddiehanna www.philly.com/christiechronicles

Inquirer staff writer Andrew Seidman contributed to this article.