The prosecution's key witness is back on the stand at the George Washington Bridge lane-closing trial.

Former Port Authority executive David Wildstein, who pleaded guilty and is cooperating with prosecutors, faces cross-examination Tuesday.

Before the trial broke for the Jewish new year on Monday, an attorney for one of New Jersey Gov. Chris Christie's former aides raised questions about Wildstein's credibility. Michael Critchley, Bridget Kelly's defense attorney, called David Wildstein a liar.

Kelly, who was Christie's deputy chief of staff, and former Port Authority of New York and New Jersey executive Bill Baroni are facing civil rights and wire fraud charges.

Wildstein has testified Christie was told about the traffic jam while it was underway. Christie has repeatedly denied that and has not been charged with a crime.