According to the AP, Lautenberg, a New Jersey Democrat, "called it 'shocking' that Christie appears to have conducted a political campaign from the U.S. Attorney's Office."
Of course, Lautenberg's call for a federal probe itself likely has a good degree of political calculation to it. Christie is locked in a tight race with incumbent Democrat Jon Corzine.
But that doesn't make the evidence against Christie any less damning.
Late Update: Here's the full statement from Lautenberg, which specifically refers to Brown:
"It is shocking to learn that a former deputy to Chris Christie was conducting a political campaign within the U.S. Attorney's Office. It was particularly distressing that this raw political agenda came into an office with a historic reputation for fair and unbiased dispensation of justice, and Ms. Brown went so far as to try to bring political campaign objectives into the planning of law enforcement actions. The Department of Justice must initiate an investigation into this matter. Nonetheless, I am confident that with its new leader in place, the U.S. Attorney's office will meet its obligation to enforce the law with integrity and fairness - free from political interference.