David Wildstein repeatedly asserted his right to remain silent on the advice of his lawyer. He had fought the order to appear before a committee, but a state judge earlier in the day said it was proper that he be subpoenaed to appear.
Still, committee members went on asking him questions for an hour, almost all of them relating to emails and text messages Wildstein previously provided the committee.
The legislative panel is investigating why the lanes were suddenly closed in September, causing traffic gridlock in Fort Lee. Other officials have said Wildstein ordered the closures. Emails and text messages revealed Wednesday that Christie's aides may have been out to punish the town's mayor for not endorsing the governor.
Assembly Transportation Committee chairman John Wisniewski, a Democrat, said the contempt matter could be followed up by a prosecutor. The penalty would be up to 18 months in prison, but people convicted of such offenses generally are not jailed.
His lawyer, Alan Zegas, told lawmakers he was invoking his Fifth Amendment right to remain silent out of fear of being prosecuted.
"He has the right to not give answer by a prosecutor who were to charge him," Zegas said, "even if he were to charge him wrongly."
One lawmaker, Democrat Thomas Giblin, pleaded unsuccessfully for Wildstein to speak, telling him he shouldn't become "a fall guy."
Wildstein resigned last month as Christie's No. 2 appointee at the Port Authority of New York and New Jersey. He knew Christie in high school, but Christie denies the two had a close, personal relationship.
Wisniewski said his committee would issue subpoenas to other officials involved, including Bridget Anne Kelly, a gubernatorial aide who was fired Thursday, and Bill Stepien, who was ousted as chairman of the state Republican organization.