Sen. Frank Lautenberg (D-NJ) has released a letter he sent today to the Justice Department calling for an investigation into the possible politicization of the U.S. attorney's office in New Jersey in the service of Chris Christie's campaign for governor.

In the letter to Mary Patrice Brown, who runs DOJ's internal ethics unit, Lautenberg, the chair of the Jon Corzine campaign, focuses on ties between Christie, a Republican, and his former top aide Michele Brown, which Lautenberg says raise "serious concerns." We laid out many of those ties here.

But one allegation, cited by Lautenberg, that hasn't received much attention lately concerns a meeting attended by Brown and held at Christie's home in January, after he had resigned as U.S. attorney but Brown remained a top prosecutor. According to Lautenberg, citing a report by NJPoliticker.com, three top Christie political hands were at the meeting, raising the concern that Brown may have participated in a political strategy session.

You can see the letter here. Lautenberg first announced his call for a criminal probe yesterday, in response to a New York Times report containing new details on Brown's apparent help for Christie.