The law firm that produced the report that cleared Gov. Christie of wrongdoing in the George Washington Bridge controversy recently donated $10,000 to the Republican Governors Association, which Christie leads.

Gibson, Dunn & Crutcher made the donation to the RGA on March 18, according to IRS filings made public Tuesday. The firm made the donation nine days before releasing its report on Christie's administration.

Christie has been chairman of the RGA since November, traveling out of state to drum up donations for fellow Republican governors. In that time period, the RGA has raised $33 million.

Pearl Piatt, a spokeswoman for Gibson Dunn, said Wednesday the firm's donations to the RGA "long predate our retention by the Office of the Governor and even predate when the current governor was first elected to office."

The international firm – which has several U.S. offices, including in New York and Washington – has been donating regularly to the RGA since 2009, in amounts ranging from $10,000 to $20,000 a year.

Piatt said the donations have been made "at the behest of" Bill Kilberg, a partner in the firm's Washington office who has been active in the RGA since 2009.

Kilberg's wife, Bobbie Kilberg, is a technology executive and prominent Republican donor. She gave the RGA $15,000 in March, according to the IRS filings.

A spokesman for Christie did not return a request for comment on the firm's donation.

At a town-hall event Tuesday, Christie voiced support for an end to campaign-contribution limits, arguing that "the idea you're going to take money out of politics is just not going to happen." Donations should be transparent, he said.

Christie's administration retained Gibson Dunn at a cost of $650 an hour in January to perform an internal review of the bridge controversy. The firm, which released its findings March 27, said Christie did not know of the September lane closures beforehand and was not involved in the decision to close the lanes.

The firm's report also dismissed as false claims by Hoboken Mayor Dawn Zimmer that Christie officials tied the release of Hurricane Sandy aid to approval of a redevelopment deal in the city.

Critics have questioned the report's credibility, in part because the firm was not able to interview the two aides it said were responsible for the lane closures. Also not interviewed were several other key figures, including at the Port Authority of New York and New Jersey.

The firm released interview summaries with 75 people – including Christie – earlier this week.

What the firm's services will cost the state is not clear. The state's acting attorney general recently said that Gibson Dunn had yet to submit any bills. Last month, the New York Times reported the firm's costs would be at least $1 million.