The legal battle between OpenAI and its co-founder-turned-rival Elon Musk has taken another sharp turn. OpenAI is now pressing Meta to turn over documents that could reveal whether CEO Mark Zuckerberg secretly coordinated with Musk on a massive $97 billion bid to acquire the ChatGPT-maker earlier this year.

According to a court filing made public on Thursday, OpenAI’s legal team claims it has reason to believe that communications between Musk and Zuckerberg exist regarding xAI’s proposal to purchase OpenAI in February. The filing suggests these discussions could have included financing and investment strategies. OpenAI is asking a judge to force Meta to comply with a subpoena issued in June after the social media giant refused to cooperate.

Meta formally objected to the subpoena in July, but OpenAI insists the documents are relevant, especially since Musk’s lawsuit revolves around OpenAI’s restructuring and recapitalisation. The request also covers Meta’s internal deliberations about OpenAI’s future—an area Musk claims the company mishandled when it shifted from its nonprofit roots.

In response, Meta spokesperson Andy Stone pointed to a line in OpenAI’s own filing which admitted that neither Zuckerberg nor Meta signed Musk’s letter of intent to buy the company. Meta declined further comment. OpenAI and Musk’s lawyers have also remained silent on the latest filings.

Back in February, Musk’s $97 billion bid was dismissed almost instantly by OpenAI CEO Sam Altman, who described the offer as “ridiculous.” He later reinforced that stance publicly, stating that OpenAI was “not for sale.” The company has argued in court that Musk’s attempt to purchase it contradicts his own lawsuit, in which he accuses OpenAI of betraying its original nonprofit mission.

The legal feud has exposed the deep rivalry between Musk and OpenAI, the very company he helped establish in 2015 before departing in 2018 over disagreements on its direction. Since then, Musk has been one of the company’s fiercest critics, while simultaneously building his own competing AI venture, xAI.

The potential involvement of Zuckerberg adds yet another intriguing layer. While there is no evidence so far that Meta formally joined Musk’s takeover attempt, reports indicate the company has been aggressively pursuing ways to catch up in the AI race. Meta has reportedly invested $14 billion in Scale AI and approached other labs with acquisition offers. The company has also poached several high-profile OpenAI researchers, including Shengjia Zhao, a co-creator of ChatGPT, who now heads Meta’s new Superintelligence Labs.

Despite years of tension between Musk and Zuckerberg—ranging from disputes over rocket safety to Musk’s joking proposal of a cage fight—the competitive pressures of artificial intelligence appear to have shifted the dynamics. Industry insiders believe the possibility of collaboration, even if limited, reflects the growing dominance of OpenAI and the urgency felt by its rivals.

For now, the question remains whether the court will side with OpenAI and force Meta to open its books, potentially shedding light on whether two of Silicon Valley’s biggest rivals ever considered joining forces in an audacious bid to control the future of AI.