The highest ranking member of the Christie Administration to give sworn testimony is the latest official to deny involvement in the decision to close access lanes at the George Washington Bridge.

Kevin O'Dowd is sworn in before the legislative Bridgegate committee (NJ TV)

On Monday, Christie's chief of staff, Kevin O'Dowd also told the legislative committee probing Bridgegate that he doesn't know what he could have done differently to prevent the unannounced lane closures.

"I would like to start my appearance today by making very clear to the committee that I had no prior knowledge of, or played no role in, the decision to close the lanes at the bridge last September," said O'Dowd under oath.

The Select Committee on Investigation grilled O'Dowd for roughly seven hours. He was asked by one panel member if the thought former Port Authority official David Wildstein ordered the lanes to be shut down.

"I think out of respect to this committee and the multiple ongoing inquiries, I don't think I should venture a guess. I don't know the answer," O'Dowd said. "I never conducted my own investigation to figure out what went on here. I didn't engage in that."

As chief of staff, O'Dowd was the direct boss of former deputy chief of staff Bridget Kelly who was ordered to be fired by Christie after her now infamous "Time for some traffic problems in Fort Lee" email went public. Kelly was fired the same day Christie cut ties with his two-time campaign manager Bill Stepien, who was a surprise member of the gallery at Monday's hearing. He did not speak with reporters.

Both Kelly and Stepien refused to turn over documents subpoenaed by the SCI. Their lawyers successfully argued before a judge that handing over the information requested would violate their Fifth Amendment rights.

In December, Gov. Chris Christie nominated O'Dowd to be the next state attorney general. Most insiders feel that with his Bridgegate testimony behind him, O'Dowd could get a confirmation hearing before the end of June.

Kevin O'Dowd (left) and his attorney Paul Zoubek speak before O'Dowd's testimony before the legislative Bridgegate hearing (Kevin McArdle, Townsquare Media NJ)

In previous testimony, Kelly was described by other witnesses as overwhelmed, emotional, paranoid and not capable of making a decision. O'Dowd said he viewed Kelly very differently and that's why he believed her when she first told him she had no involvement in the growing scandal. O'Dowd told the committee that he was directed by Christie to ask Kelly if she had anything to do with the lane closures and when he did she said, "Absolutely not." O'Dowd was asked why he thought her answer was credible.

"Bridget Kelly is someone that I had worked with and known for four years. Someone who I thought very highly of, hardworking, energetic, loyal, someone who I believed and trusted," O'Dowd said.

The co-chairs of the SCI plan to have the panel take a break until after the July 4 holiday.