Facebook Founder Mark Zuckerberg had to answer several questions during a trial of a lawsuit related to the Ocolus Rift VR headset. The lawsuit has been filed to make the Facebook founder cough up billions of dollars.

Bethesda Softworks owner ZeniMax Media waged a lawsuit worth $2 billion against the Facebook founder over the alleged theft of intellectual property that helped in the creation of Oculus Rift VR headset, Entrepreneur reported. Of course Zuckerberg denied the allegations.

Apparently, John Carmack, who currently serves as chief technology officer of Oculus, was a former employee of ZeniMax Media. The Bethesda Softworks owner claims that Carmack stole the technological foundation that helped Oculus build its VR headset.

Zuckerberg denied having any knowledge of potential thievery involving Oculus. A letter was dissected in court as it mentioned the legal consequences of stolen technology, but Zuckerberg dismissed the idea that it has something to do with the Oculus Rift VR headset, Mercury News reported.

Zuckerberg said it is normal to raise potential problems during an acquisition. He acquired Oculus for $2.3 billion.

The Facebook founder also took a jab against Google and Apple, whose operating systems do not allow any tinkering from outside people. He said the closed nature of the systems prevent his company from designing technology that people will enjoy.

ZeniMax Media is insisting that Oculus is using trade secrets and confidential information that Carmack stole from the company. It also believes that Zuckerberg and his company is trying to hide the trail of the alleged thievery.

Aside from stealing company information, ZeniMax Media is also accusing Carmak of pirating its employees. Oculus called the lawsuit wasteful, and it does not believe that Zenimax Media has enough claims to pursue damages.

Jobs & Hire previously reported that Zuckerberg is included in the list of billionaires that are under 40 years of age.