TRENTON — The legal tab for taxpayers topped $7.75 million for the private law firm hired by Gov. Chris Christie in the wake of the George Washington Bridge lane closings scandal, according to the latest billing vouchers through April.

The heavily-redacted bills the state Attorney General's Office released late Friday in response to a public records request represent the money earned by the law firm, Gibson, Dunn & Crutcher, which represents the governor in the investigation into the September 2013 lane closings.

Last week, prosecutors unsealed an indictment against Christie's former deputy chief of staff Bridget Kelly and former Port Authority deputy executive director Bill Baroni for allegedly orchestrating the lane closures. The motive, according to the indictment, was political payback against the Democratic Mayor of Fort Lee, Mark Sokolich, who did not endorse the governor during his reelection campaign. Kelly and Baroni pleaded not guilty on Monday.

David Wildstein, also a former Port Authority official, pleaded guilty last week to two counts of conspiracy in exchange for his cooperation.

Gibson Dunn attorneys bill at $350 an hour, according to the Attorney General's Office. The firm billed $32,088 in December; $106,325 in February, $37,731 in March; and $53,824 in April, the attorney general's office said.

Taxpayers also have paid $1.2 million last year to private law firms retained by other state employees embroiled in the scandal.

The law firm last year produced a report written by former federal prosecutor and firm partner Randy Mastro that said the governor had no knowledge or involvement in the scheme.

The legislative committee investigating the land closures has spent just under $1 million in legal fees, co-chairman John Wisniewski said,

NJ Advance Media staff writer Samantha Marcus contributed to this report.

Susan K. Livio may be reached at slivio@njadvancemedia.com. Follow her on Twitter @SusanKLivio. Find NJ.com Politics on Facebook.