ZeniMax Media, the parent company of both Bethesda Softworks and Id Software, says it will prove at trial that John Carmack and others at Oculus stole trade secrets to "misappropriate" virtual reality technology that was first developed while Carmack was working at Id Software. What's more, ZeniMax is now accusing Oculus of "intentional destruction of evidence to cover up their wrongdoing." Mark Zuckerberg, CEO of Oculus parent company Facebook, is scheduled to respond to those accusations in testimony starting tomorrow, according to a report by Business insider.

"With the start of the trial of our case in Federal District Court in Dallas against Defendants Facebook, Oculus and its management, ZeniMax and id Software welcome the opportunity to present substantial evidence of the Defendants' misappropriation of our Virtual Reality (VR) intellectual property," ZeniMax wrote in a statement given to Ars.

"That evidence includes the theft of trade secrets and highly confidential information, including computer code. ZeniMax will also present evidence of the Defendants' intentional destruction of evidence to cover up their wrongdoing. ZeniMax and id Software are the visionary developers of breakthrough VR technology and look forward to the vindication of our claims."

ZeniMax's statement comes after Carmack testified at trial last week, saying the case was "ridiculous and absurd." His testimony echoed Oculus' initial reaction when ZeniMax's accusations first surfaced in 2014.

In court filings leading up to the trial , ZeniMax detailed its case that Carmack, while still an employee at Id Software, "designed the specifications and functionality embodied in the Rift SDK and directed its development." Carmack's technology and guidance allegedly "literally transformed" Oculus founder Palmer Luckey's early Rift prototype from a "primitive virtual reality headset" that was "little more than a display panel." Carmack allegedly used "copyrighted computer code, trade secret information, and technical know-how" from his time at ZeniMax after he moved to Oculus as CTO in 2013

"Luckey lacked the training, expertise, resources, or know-how to create commercially viable VR technology," ZeniMax argues in its amended complaint. "His computer programming skills were rudimentary, and he relied on ZeniMax's computer program code and games to demonstrate the prototype Rift. Nevertheless, this fraudulent tale was frequently reported in the media as fact."

As the trial began last week (as reported by a Law360 summary , registration required), Carmack told the court of his development of a virtual reality demo forin 2012 and his search for a VR headset that would be suitable to run it. That's when he says he got in touch with Luckey, leading to the now legendary E3 2012 demo that introduced Oculus to the public.

Carmack said at trial that although ZeniMax initially agreed to share code with Oculus to both companies' mutual benefit, negotiations for ZeniMax to get an ownership stake in the nascent VR firm fell apart. As such, Carmack says he was told to stop working on virtual reality, a decision he said at trial was "very poor" and led to his eventual departure for Oculus.

While Carmack admitted to copying thousands of e-mails to a personal hard drive on his last day working for ZeniMax, he testified that he didn't use this code while at Oculus. Instead, Carmack says he rewrote the technology used in the Rift and Gear VR headsets from scratch and that the code he had written at ZeniMax wouldn't even work in the current Oculus headsets.

ZeniMax is seeking $2 billion in damage, which matches the value that Facebook paid for Oculus in 2014. The trial is expected to last three weeks.