An internal Justice Department investigation into the online commenting scandal at former U.S. Attorney Jim Letten’s office “unequivocally concluded” that top Letten lieutenants Jan Mann and Sal Perricone “engaged in extensive and intentional prosecutorial misconduct.”

But the 152-page report by the Justice Department’s Office of Professional Responsibility also found that Mann and Perricone were likely the only prosecutors in the office who engaged in such online hijinks and that Letten — who was brought down by the scandal — was likely unaware of the duo’s exploits until they were exposed publicly.

The OPR report, much like a separate inquiry into Letten’s shop that was overseen by prosecutor John Horn, of Atlanta, remains hidden from public view, with the Justice Department thus far refusing to release it. The report was completed about six months ago.

But a synopsis of the findings was made public late Tuesday by U.S. District Judge Mary Ann Vial Lemmon and U.S. Magistrate Judge Joseph Wilkinson, who read the report and concluded it would not help Stacey Jackson’s defense.

Jackson is accused of taking kickbacks from contractors she hired to work for the city-funded nonprofit she headed, New Orleans Affordable Homeownership. Her lawyer, Eddie Castaing, sought access to the OPR report in hopes of bolstering a broader claim that Jackson is the victim of prosecutorial misconduct.

In a joint ruling, Lemmon and Wilkinson rejected that request, saying the report wouldn’t do anything for Jackson — although they hinted it might be of use to other defendants, and said it might well be “material and discoverable” in other criminal cases.

The judges also pulled the plug on Jackson’s efforts to unmask two other nola.com commenters that the former city official suggested were federal officials. The first, “aircheck,” was the subject of a subpoena issued to nola.com, which turned over a raft of materials to the court last month after failing to persuade Wilkinson and Lemmon that the commenter’s First Amendment rights as well as those of the media organization were being violated.

The judges have been reviewing those documents, the motion says, but they’ve been unable to determine the identity of “aircheck” — who apparently used various devices to post comments, and posted from a range of locations — and they conclude that further study of the issue is pointless. (A second commenter who Jackson had suggested might be a federal official, “jammer1954,” was also the subject of a subpoena; that commenter has been identified by the judges as a private citizen.)

Lemmon and Wilkinson also shot down a more recent motion by Castaing to unmask the commenter “kefir,” who Castaing surmised might be Mann, Perricone or possibly Jim Mann, Jan Mann’s husband and also a former federal prosecutor. The judges ruled that the “kefir” postings “are not sufficiently similar to the comments known to be attributable to Jan Mann and Perricone in tone, word choice, frequency, style or content” to warrant further scrutiny. They said there is no basis for implicating Jim Mann in the commenting scandal, noting that the two separate Justice Department inquiries failed to show he was aware of the postings by his wife and Perricone, who was a close friend.

The joint ruling by the two judges seems to shut down one of the last ongoing efforts to wring new facts — and perhaps new legal fallout — from the commenting scandal, which has already wrought impressive damage. And it would seem to clear the way for Jackson’s upcoming trial, scheduled to begin July 21. While her motion to quash her indictment on the basis of prosecutorial misconduct remains pending, it seems unlikely to be granted in light of Tuesday’s ruling.

More significantly, the judges’ motion is by far the most complete look the public has gotten at the OPR investigation, and it may remain that way, assuming the Justice Department doesn’t opt to release the report.

The judges describe the report — dated Dec. 13, 2013, and running 152 pages, plus more than 100 pages of “exhibits and related correspondence” — as “more broad-ranging than the so-called Horn report,” which largely focused on the conduct of prosecutors and other Justice Department personnel in the Danziger Bridge case.

“The OPR report examined in broader terms the possibility of wider-ranging prosecutorial misconduct in other matters, not just by Mann and Perricone but also by others in the office of Jim Letten,” the two judges wrote.

“The overall conclusion of the OPR report is that prosecutorial misconduct of the kind committed by Perricone and Mann was confined to them and was neither sanctioned by the United States attorney nor engaged in by others in the office,” the ruling said, adding that it’s not clear whether Mann and Perricone even know of each other’s postings.

Moreover, the judges said, the report “concludes that there is ‘no evidence establishing’ that anyone in the U.S. Attorney’s Office, apart from Mann and Perricone, engaged in misconduct of any kind. It concludes that while others in the office may have suspected that Perricone was posting, none actually knew that he was, and none knew or suspected that Mann was posting comments online about office matters.”

More broadly, the OPR investigation apparently found no evidence that the nola.com rants by Mann and Perricone were part of a broader “pattern, policy or practice to influence public opinion about the guilt of defendants or targets of investigations” being conducted by the office.

The report also says investigators found no evidence that other prosecutors or employees of the U.S. Attorney’s Office made inappropriate posts, but that they cannot state with certainty that such postings never occurred “without access to information protected by nola.com.”

Follow Gordon Russell on Twitter, @gordonrussell1.