Federal prosecutors from the U.S. Attorney's Office in Newark on Friday met privately with the chief lawyer for New Jersey lawmakers investigating the George Washington Bridge traffic jams and requested that the panel not take any steps that might interfere with its criminal probe, according to two sources familiar with the matter.

The meeting, coming the same day that former Port Authority official David Wildstein's lawyer released a letter that said his client has "evidence" that might contradict Christie's public account, was the latest indication that U.S. Attorney Paul Fishman's office is aggressively investigating the so-called Bridgegate affair.

At the meeting, federal prosecutors asked that the special New Jersey legislative committee give them a heads up about any witnesses they might seek to call, said the sources, who spoke with NBC News on condition of anonymity. The prosecutors want time to raise any objections that public testimony might compromise their own investigation.