Sam Altman, the face of the artificial intelligence revolution, will not return as OpenAI chief executive despite talks to renegotiate his return Sunday, a person familiar with the matter said, the latest twist in one of Silicon Valley’s most dramatic boardroom showdowns.

Emmett Shear, the co-founder of Twitch, a popular video game streaming platform Amazon acquired in 2014, will be named the company’s interim chief, replacing Mira Murati, who was named interim CEO in a management reshuffle Friday, this person said.

The latest development came after a chaotic weekend, where OpenAI investors and employees, blindsided by the board’s move to fire Altman on Friday, mounted a campaign to get him reinstated. In its vague statement explaining the rationale for his ouster, OpenAI had said Altman wasn’t always “candid” in his communications with them. The news reverberated through Silicon Valley and the halls of government, where Altman had become a major influencer of policy and regulation on AI.

Shear stepped down as Twitch’s CEO in February, and was named a part-time adviser to companies at Y Combinator, an influential San Francisco startup incubator that Altman himself was head of from 2014 to 2019.

This story is breaking and will be updated.