NEW ORLEANS (AP) — A federal prosecutor in New Orleans has been removed from cases after acknowledging he has been anonymously posting comments on a newspaper's website about targets of federal probes, politicians, judges and even his own colleagues, U.S. Attorney Jim Letten announced Thursday.

Letten said Assistant U.S. Attorney Salvadore Perricone told him Tuesday that he made hundreds of posts at nola.com, the companion website of The Times-Picayune, under the username "Henry L. Mencken1951."

One of the cases he has commented on — and worked on — involves a suburban New Orleans landfill at the center of a federal investigation. On Monday, River Birch landfill owner Fred Heebe sought a state court order to question Perricone under oath about whether he posted negative comments about him under the Mencken username.

Letten said he has referred the matter to the Justice Department's Office of Professional Responsibility, which will decide if any discipline is warranted.

Letten said Perricone has been removed from "all matters" discussed in his Web posts, but he wouldn't specify which cases. He expressed hope that Perricone's actions haven't damaged any of the cases he has handled.

"Sal is a professional and readily acknowledged his conduct," Letten said. "I think it would be inappropriate for me to characterize what his emotional display was, but he was extremely forthright and professional in his acknowledgment to me."

Perricone didn't immediately respond to a message seeking comment.

Heebe hasn't been charged with a crime, but River Birch Birch CFO Dominick Fazzio is charged with plotting to defraud a construction management company. Perricone is one of the prosecutors assigned to that case and participated in a hearing this week on it.

River Birch and Perricone also are involved in the federal case against a former Louisiana wildlife official who pleaded guilty last year to charges he took more than $463,000 in payoffs from a landfill company owner's businesses to reward him for work in trying to keep a rival landfill closed.

The landfill company owner is identified only as "co-conspirator 'A'" in the indictment against former state Wildlife and Fisheries Commissioner Henry Mouton, but the document says Mouton touted River Birch. The company is co-owned by Heebe. Perricone also worked on Mouton's case.

"Mencken" invokes the name of a famous Baltimore Sun columnist from the early 20th century. Roughly 600 comments had been posted on nola.com under the username.

Before Letten revealed that Perricone wrote those posts, Heebe's lawyers argued the author of them seemed to have a "keen awareness" of the inner workings of Letten's office and routinely expresses dismay that rank-and-file prosecutors don't get more credit.

"Another Letten news conference?" one post said. "Letten is great for taking credit for other people's hard work. It is the assistants and agents who do the work and should be congratulated."

Letten said he wasn't concerned about being a target of Perricone's biting comments.

"My hide is pretty thick," he said.

Perricone also posted a comment last year about U.S. District Judge Helen "Ginger" Berrigan, who presides over the case against Fazzio. He described her as someone who "loves killers."

Other subjects of his comments include New Orleans Mayor Mitch Landrieu, New Orleans Police Superintendent Ronal Serpas and President Barack Obama. One of his posts expresses the view that "Obama and his West Wing band of Bolesheviks have a master design to strangle America's economy."

The author of the Mencken posts identified himself as a 75-year-old retired lawyer who graduated from law school in 1951, but Heebe's lawyers cast doubt on that description and noted that Perricone was born in 1951.

"Assuming a person does not skip a grade of formal education and has no delay between undergraduate and graduate education, the earliest age at which one can complete law school is 25," their filing says. "A person who was 25 in 1951 would have been born in 1926 and thus would be 87 years old today, not 75."

Heebe and his attorneys, who vowed to sue the author of the posts, didn't immediately return calls seeking comment Thursday.

Perricone didn't stop posting comments even after Heebe's court filing led to him telling Letten about his online alter ego.

"I'm here," he wrote Wednesday after other nola.com commenters wondered if he would resurface. "Watching our rights erode."