NEW ORLEANS — It is not at all unusual for the goings-on at the United States attorney’s office to be a prime subject of conversation here, where corruption has a long and well-chronicled history. What is unusual is that the office itself, and not one of the politicians it is prosecuting, is the focus of all the talk.

This month, a bizarre legal tale that has been simmering for months took a more serious turn when the first assistant United States attorney, essentially the office’s second in command, was exposed for participating under an alias in the rancorous comments section of a local news Web site.

She was the second prosecutor from the office to be found offering extracurricular commentary on the Web site, nola.com, frequently on cases the office is pursuing.

These exposures have imperiled the reappointment of Jim Letten, the longest-serving United States attorney in the country. And they come with an intriguing twist: the person who has made the exposures, a landfill magnate named Fred Heebe, is an investigative target of the office.