Gov. Chris Christie’s longtime press secretary is set to tell a New Jersey legislative committee what he knew about a political retribution plot carried out by former aides to the governor.

Michael Drewniak is the only witness scheduled to testify Tuesday. Two others will appear next month as the committee attempts to determine who ordered the approach lanes of the George Washington Bridge to be blocked without notice last September, and why the Democratic mayor whose town is at the base of the heavily traveled span was targeted for payback.

“The hearing is going to be an effort to continue to fill in the blanks on the record that we have so far,” said Assemblyman John Wisniewski, co-chairman of the legislative panel. “The picture that has been provided to us by emails and other documents leaves lots of questions unanswered as to why certain actions were taken and, just as importantly, why certain actions weren’t taken.”

The plot carried out while Christie was running for re-election has become a major distraction as the Republican contemplates a 2016 presidential run. A federal criminal investigation is underway in addition to the legislative inquiry.

Drewniak has worked for Christie for 14 years, starting when Christie was New Jersey’s top federal prosecutor. Christie recruited Drewniak and many assistant prosecutors after winning the 2009 gubernatorial election.

Drewniak had a professional and social relationship David Wildstein, a key figure in the case. The Christie administration approved the creation of a $150,000 job for Wildstein at the Port Authority of New York and New Jersey, the agency that operates the bridge. But Wildstein was forced to resign from the post in January, after his involvement in the lane closings was revealed.

It was Wildstein who replied, “got it,” after Christie aide Bridget Kelly sent him an email saying, “time for some traffic problems in Fort Lee.”

Drewniak had dinner with Wildstein the evening before he resigned and helped draft the administration’s response to the resignation. Afterward, Wildstein thanked Drewniak for his advice.

Drewniak was interviewed three times by lawyers hired by Christie to review the lane closings. Their report found that Kelly and Wildstein acted alone in ordering the lanes closed for an unknown political vendetta.

Drewniak also was grilled for two hours by the Christie administration in January, after which the governor decided not to fire him.

The legislative panel heard from Christina Renna last week. Renna, who worked for Kelly while the lanes were blocked, described her former boss as erratic and overwhelmed but said she would not have decided to cause traffic jams without orders to do so.

(AP)