The fourth week of the Bridge-Gate trial began Tuesday with testimony from a former Christie staffer and a Port Authority police officer.

Port Authority Officer Paul Nunziato testified that he was pressured to help cover up the Fort Lee lane closing conspiracy.

Nuziato says he originally put out a false statement on behalf of his police union that took credit for the lane closing in an effort to help alleged Bridge-Gate conspirators Bridget Kelly, Bill Baroni and David Wildstein cover up the plan. He says he lied about the purpose of the closings to protect his union members from Port Authority bosses.

The officer also testified that Baroni tried to pressure him into saying the lane closings were his idea.

"It was a furtherance of his protection of his members and he's proud of that. He's proud - of a difficult, an almost impossible position he was in," says Nunziato's attorney.

A former staffer for Gov. Chris Christie also took the stand Tuesday. Deborah Gramiccioni described a "thunderously angry" Gov. Christie once the conspiracy came to light.

Gramiccioni says that the governor called his senior staff into a meeting an hour before his December 2013 news conference addressing the lane closings. She says the governor screamed at his staff during the meeting and told them to turn over any information or emails they may have had pertaining to the lane closings.

Gramiccioni also testified that Kelly sat in her office crying after the governor's angry announcement. But Kelly's defense attorney say that she had already turned over her emails a day before the meeting.

Kelly's attorney then went on to say that Gov. Christie lied to the public when he said that he had no knowledge that his senior staff knew about the lane-closing plot.

Gramiccioni says that she was recently nominated to the New Jersey Supreme Court by the governor.

The trial is expected to resume Wednesday.