The law firm hired by Gov. Christie's office in 2014 to investigate the George Washington Bridge lane-closure scandal interviewed more than 70 witnesses and reviewed more than 250,000 documents to produce a 360-page report that it said cleared the governor of wrongdoing.

How, then, did the firm, Gibson, Dunn & Crutcher L.L.P., not take or preserve any notes during its investigation, apart from summaries it would later release to the public?

That's what attorneys for two former allies of Christie's who face federal criminal charges in the case are asking in newly filed court documents. Gibson Dunn has said some of the records don't exist and asked a judge to quash a subpoena seeking others.

"In sum, the firm claims that it billed New Jersey taxpayers nearly $10 million . . . but that not a single lawyer took a single note during 75 interviews in the most high profile political case in recent years," lawyers for Bill Baroni, a former top official at the Port Authority of New York and New Jersey, wrote in documents filed Monday.

"That assertion defies common sense, the practice of law and Gibson Dunn's own policies and procedures with respect to every other internal investigation it has conducted. It simply cannot be the case."

Gibson Dunn has billed the governor's office for nearly $8 million for investigating the bridge controversy, according to invoices released by the state in May.

The firm's report also dismissed allegations of abuse of Sandy funds by members of the Christie administration, as has U.S. Attorney Paul Fishman's office.

"Given the financial windfall [Gibson Dunn] reaped from the purely voluntary investigation, it is hardly a burden to expect [Gibson Dunn] to attempt to retrieve the notes they were required to maintain and attempted to delete or copy over," wrote Michael Critchley, an attorney for Bridget Anne Kelly, Christie's former deputy chief of staff.

The records could be important to Kelly's defense, he wrote, in part because at least two former top officials in Christie's administration testified under oath before the Legislature that Gibson Dunn's report mischaracterized their interviews.

Federal prosecutors allege that Baroni and Kelly conspired to close lanes at the bridge from Sept. 9 to 13, 2013, to punish a local Democratic mayor who didn't endorse Christie's reelection. David Wildstein, a former Port Authority official who worked for Baroni, has pleaded guilty and is cooperating with the government.

The scandal has spawned other investigations, including into the Port Authority, which recently forced the resignations of three top executives at United Airlines.

It has also weighed on the Republican governor's bid for the presidency.

Gibson Dunn says it has complied with part of the subpoena, which seeks "any and all handwritten or typed notes, stenographic transcripts and audio and/or video recordings of witness interviews conducted by Gibson Dunn" during its representation of Christie's office, as well as "any and all metadata and the document properties for all typed notes and interview summaries created during interviews of witnesses."

U.S. District Judge Susan D. Wigenton approved the subpoena in July. She said the information sought by the subpoena was "clearly relevant" and that the request appeared to have been made in "good faith."

In August, Gibson Dunn said it had "effectively complied with the subpoena" by producing interview memoranda it conducted during its internal investigation. The firm said "no notes, transcripts, and recordings of the witness interviews exist separate from the interview memoranda."

The request for metadata should be quashed, Gibson Dunn said, because the defendants did not demonstrate that the metadata were "relevant and admissible on any issue that will arise at trial and is specifically identified, as required under controlling law."

Defense attorneys shot back in court filings Monday that Gibson Dunn's arguments had already been rejected by the judge when she granted the subpoena in July.

Moreover, they said, Gibson Dunn had not proved or even argued that complying with the subpoena would be "unreasonable or oppressive," the standard by which the firm could challenge the request.

Critchley wrote that Gibson Dunn had not tried to recover the documents, which he said the firm was required to maintain under state guidelines for seven years.

Gibson Dunn has said in court filings that "witness interviews were summarized electronically by one attorney" while they were being conducted "and then edited electronically into a single, final version."

The words single, edited, and final indicate there were previous and multiple versions of those documents, Critchley wrote.

Retrieving any notes would be important, he said, because the interview memoranda may be "unreliable."

Critchley noted that a former Christie staffer who worked under Kelly took issue with parts of Gibson Dunn's characterization of her interview.

For example, while testifying before a legislative panel in May 2014, Christina Renna objected to Gibson Dunn's assertion that staffers in her department received "mandatory directives" not to return calls to certain mayors.

Christie's former chief of staff, Kevin O'Dowd, also disputed part of a Gibson Dunn interview summary when he testified before the Legislature.

The metadata include such information as the names of the lawyers who wrote the interview memoranda.

Critchley said this information is needed so Kelly may confront those at Gibson Dunn whose memoranda have been discounted or challenged.

Critchley said he expected both Renna and O'Dowd would be witnesses at trial, which is to begin in March.

Baroni's attorneys said that at a minimum the judge should appoint a "neutral computer expert" to examine Gibson Dunn's files to determine whether previous drafts of the interview memoranda exist.