A group of app developers is suing Facebook over an alleged “anticompetitive scheme” and monopolistic behavior, according to NBC News.

In a proposed class-action lawsuit, “a group of companies behind now-defunct Facebook apps is suing the social media giant, claiming illegal monopolistic behavior.” The lawsuit is based on documents that NBC News and other journalists gained access to last year, and that paint a less-than-appealing picture of Facebook, and Mark Zuckerberg in particular.

According to those documents, Zuckerberg and other Facebook executives, used user data as a bargaining chip to keep other app developers in line, all the while portraying the moves as being in the interest of protecting user privacy.

The complaint alleges that “this action seeks to halt the most brazen, willful anticompetitive scheme in a generation — a scheme that verges on final, irreparable completion as of the date of this Complaint. Facebook stands today as a paragon of unbridled market power.”

The Mercury News quotes Yavar Bathaee, a partner at law firm Pierce Bainbridge and co-lead counsel as saying: “Facebook faced an existential threat from mobile apps, and while it could have responded by competing on the merits, it instead chose to use its might to intentionally eliminate its competition.”

This is just the latest scrutiny and legal challenges Facebook has faced, both in the U.S. and in Europe. For a company trying to reassure users and legislators alike that it can play fair, this is the last thing the company needs.