A research website company filed FindTheBest.com Inc. v. Lumen View Technology LLCon Monday in the Southern District of New York. The lawsuit accuses Lumen and five related businesses and individuals of creating shell companies to extort money from legitimate businesses that aren’t infringing its patent.

The case is a response to a patent infringement complaint that Lumen filed against FindTheBest.com in May in the same district. Lumen alleged infringement of a patent for a system and method for matching two or more parties’ preferences.