Justice Department investigating its own role in warrantless wiretap case?

According to a letter which Rep. Maurice Hinchey (D-NY) received today from the Justice Department's Counsel for the Office of Professional Responsibility, the OPR has opened an investigation into "the Department of Justice's role in authorizing, approving and auditing certain surveillance activities on the National Security Agency [NSA], and whether such activities are permissible under existing law."

Here's an AP article here.

See the letter here.