"Apparently, after selling its Duke Nukem IP rights to Gearbox in 2010, 3DR sought to privately convince others that the sale never happened," the complaint reads. "The result is the unauthorized development effort that reportedly exists between 3DR and Interceptor."
Among the documents filed in the suit is a breach statement issued by Gearbox stating that 3D Realms infringed on Gearbox's intellectual property in addition to a statement signed by 3D Realms CEO Scott Miller and Duke Nukem co-creator George Broussard that acknowledged the infringement. In a statement filed to Joystiq, Gearbox Software said, "As the filing shows, 3DR's wrongdoing is both admitted and unfortunate for everyone who cares about Duke Nukem."
3D Realms filed a lawsuit against Gearbox in June 2013 for alleged unpaid royalties for Duke Nukem Forever, and later issued a public apology and withdrawal of the lawsuit in September 2013. Gearbox took over the development of the game in September 2010 in addition to acquiring the rights to the brand from 3D Realms.