TRENTON -- A top Democrat said Monday the law firm hired by Gov. Chris Christie to conduct a state-funded investigation of the Bridgegate scandal should refund $8 million to New Jersey taxpayers, saying she is "infuriated" by court testimony contradicting its findings.

"It is a legal question as to whether we can compel them to refund the money," state Sen. Loretta Weinberg (D-Bergen) told NJ Advance Media.

"But at the least, we are going to demand that they refund it first. This is a big deal. Those millions should go to programs for women's health, for education, that we've had to cut."

Weinberg served as co-chair of the Legislature's Joint Select Committee on Investigation, which conducted its own probe into the politically motivated lane closures on the George Washington Bridge in September 2013.

An internal investigation by the New York law firm of Gibson Dunn & Crutcher at the behest of the Christie administration concluded with a March 2014 report exonerating the governor.

On Friday, Christie's longtime political consultant, Mike DuHaime testified in federal court that on a phone call with the governor minutes before he held a Dec. 2, 2013 news conference, "I reiterated ... that I was told ... that (former deputy chief of staff) Bridget (Kelly) and (Christie campaign manager Bill) Stepien were aware" of the lane closures.

At that Dec. 2 press event, Christie derisively joked that he himself who'd been "working the cones." At another press conference on Dec. 13, 2013, Christie said he had "no reason to believe" any of his top aides were involved in the lane closures.

"I've made it very clear to everyone on my senior staff that if they had any knowledge about this that they need to come forward and tell me about it and they've all assured me that they don't," the governor told reporters on Dec. 13.

Federal prosecutors say the lanes were closed to punish the Fort Lee mayor for not endorsing Christie's re-election bid. An initial claim by Christie aides that the closures were part of a traffic study was discredited when Port Authority Executive Director Patrick Foye appeared before the Assembly Transportation Committee on Dec. 9, 2013 testifying he was unaware of any resulting traffic study.

A month later, after the now-infamous "Time for some traffic problems in Fort Lee" email exchange between Christie's Port Authority appointee David Wildstein and the governor's deputy chief of staff, Bridget Kelly surfaced, Christie fired Kelly "because she lied to me."

The Christie administration then retained Randy Mastro, a partner in the New York office of law firm of Gibson, Dunn & Crutcher to investigate the lane closures. Its 300 page report that made no mention of Christie's Dec. 2, 2013 conversation with Duhaime.

Instead, it stated only that "at some point between December 9 and 11, 2013, the Governor spoke on the telephone to Michael DuHaime," and that during their call, "DuHaime mentioned that he had recently spoken to Wildstein, who told him that the traffic study was Wildstein's idea and that Wildstein would take responsibility for it. In response, the Governor told DuHaime that he would talk to Stepien."

The firm ultimately billed the state $8 million for its work, with taxpayers picking up the tab for an additional $2.5 million paid to a digital forensics company.

Claude Brodesser-Akner may be reached at cbrodesser@njadvancemedia.com. Follow him on Twitter @ClaudeBrodesser. Find NJ.com Politics on Facebook.