A few months before Elon Musk left OpenAI’s board of directors in February 2018, he tried to recruit Sam Altman to join a “world-class AI lab” within Tesla. Musk went as far as offering the OpenAI CEO a Tesla board seat, according to emails and testimony presented in federal court on Wednesday during the Musk v. Altman trial. The emails were shown to a jury during the cross examination of Shivon Zilis, a former OpenAI adviser and board member who is also the mother of four of Musk’s children.

Musk’s core claim in this lawsuit is that Altman and OpenAI president Greg Brockman effectively stole a nonprofit, using the $38 million Musk invested to create a private company worth more than $800 billion today. On Wednesday, lawyers for Musk showed video depositions of former OpenAI CTO Mira Murati and former OpenAI board member Helen Toner, to raise concerns over Altman’s alleged history of deceit.

OpenAI’s legal team has responded to Musk’s claims by questioning his true motives, arguing that the Tesla CEO has had “sour grapes” ever since he failed to assume control of OpenAI in 2017. He has since started a rival, for-profit AI lab. OpenAI’s lawyers used Zilis’ cross-examination on Wednesday to bring up evidence about Musk’s alleged plans to subvert OpenAI, and tried to suggest Zilis was privy to those plans. As it pertains to this case, one of Zilis’ most important roles at OpenAI was acting as a conduit between Musk and Altman.

In a text from February 2018 presented as evidence, Zilis—then an OpenAI adviser, as well as a Neuralink and Tesla executive—asked Altman, “Did you think through a B Corp subsidiary of Tesla?”

“There was documentary evidence that, at several points, Mr. Musk had contemplated seeking to join Sam Altman to the board and offered that option,” said OpenAI lawyer William Savitt outside the courthouse on Wednesday. “It was part of Mr. Musk’s effort to corrupt OpenAI and absorb it into Tesla … he was trying to get Altman to abandon the mission and be part of Tesla.”

In an email to Tesla’s VP of communications, Sarah O’Brien, from November 2017, Zilis shared a draft of an FAQ page about an event Tesla was planning to hold at the NeurIPS AI conference. “The purpose of this event is to share that Tesla is building a world leading AI lab(?) which will rival the likes of Google / DeepMind and Facebook AI Research,” the drafted FAQ read. The document continues, “One major issue for Tesla is when people think of Elon and AI, they think of OpenAI.”

Another part of the FAQ labeled “Who?” lists several Tesla executives who were planned to lead the unit, including Musk and Andrej Karpathy, a former OpenAI researcher. Altman’s name is listed next to Musk’s with two question marks beside it.

The FAQ is marked up with notes including that Altman could be a moderator for the NeurIPS event, which “could be a forcing function for Sam to commit to TeslaAI.” Another note reads that Tesla AI’s “strategy had yet to be defined and some of it may be deeply proprietary.”

Zilis testified on Wednesday that Altman never ended up joining Tesla, and the AI lab and the NeurIPS launch event never came to fruition. She also testified that Musk reached out to Karpathy about recruiting him to Tesla. Savitt told reporters that Zilis’ testimony on Karpathy is “directly contrary to what Mr. Musk told the jury just a few days ago.” Earlier in this trial, Musk testified that Karpathy left OpenAI of his own volition.