By Joseph Tanfani, Tribune Washington Bureau

TRENTON, N.J. — A new joint investigations committee began its work Monday, seeking to unravel the mystery of who gave the order for the now-notorious traffic jam in September in the lanes leading to the George Washington Bridge.

The new joint committee reissued the 20 subpoenas that another Assembly panel issued earlier this month, many to top officials in the office of Republican Governor Chris Christie and his appointees at the Port Authority of New York and New Jersey. Democrats in the state Senate and Assembly had started separate investigations before deciding to combine their efforts.

The votes to set up the new committee were unanimous, but that’s where the bipartisan spirit ended. Assemblyman Michael Patrick Carroll, one of four Republicans on the new committee, says he sees no good reason for the investigation — other than to go after Christie.

“There’s been absolutely no credible evidence to support the idea that he was involved,” he said, adding that if there was a crime, federal prosecutors are already on the case; if the goal is reform of the port authority, the authority doesn’t need an expensive investigation. “That would lead to the impression that the direction here is less investigatory than partisan,” he said.

Republicans repeatedly tried to set boundaries on the committee’s activities but were rebuffed by Democrats, who said they never could have guessed last fall that the email trail about the lane closures would have led to Christie’s office, with a message from his now-fired deputy chief of staff: “Time for some traffic problems in Fort Lee.”

State Sen. Loretta Weinberg, a Democrat whose district includes Fort Lee, said the committee had no plans right now to look into other matters, such as the Hoboken mayor’s allegations that Christie’s top officials used recovery funds from Superstorm Sandy to try to strong-arm her into backing a development deal. But Weinberg wouldn’t rule it out, either.

“We will go wherever those documents take us,” she said. “I’m not going to make any guesses whether it leads us to Hoboken or any other towns in the state of New Jersey.”

The subpoenas ask for documents by February 3.

Other investigations are now probing the same territory.

The U.S. attorney’s office — where Christie made his political reputation as a corruption-fighting prosecutor — has been interviewing witnesses and issuing its own subpoenas. Last week, the law firm of Patton Boggs, hired to represent the Christie for Governor campaign and the New Jersey Republican State Committee, confirmed that the two organizations had also received subpoenas from the U.S. attorney’s office seeking evidence related to the bridge.

As the investigation has widened, other figures in the scandal have also brought high-powered legal talent on board. The chairman of the port authority, David Samson, has hired Michael Chertoff, former Homeland Security chief, and Angelo Genova, a prominent Democratic lawyer in New Jersey who specializes in election law. Christie has hired Randy Mastro, a former federal prosecutor now in the New York office of Los Angeles-based Gibson, Dunn & Crutcher.

The state investigative committee hired Reid Schar, a former federal prosecutor who prosecuted former Illinois Governor Rod Blagojevich.

AFP Photo/Eric Thayer