Thinking Machines Lab, the AI startup led by former OpenAI CTO Mira Murati, has lost one of its co-founders to Meta.

The Wall Street Journal reports that AI researcher Andrew Tulloch announced his departure to employees in a message on Friday. A Thinking Machine Labs spokesperson confirmed Tulloch’s departure to the WSJ, saying he “has decided to pursue a different path for personal reasons.”

Back in August, the WSJ reported that Mark Zuckerberg’s aggressive AI recruiting blitz included an offer to acquire Thinking Machines Lab — and when that failed, Zuckerberg reportedly tried to lure Tulloch with a compensation package that could have been worth up to $1.5 billion over at least six years. (At the time, a Meta spokesperson said that the WSJ’s description of the offer was “inaccurate and ridiculous.”)

Tulloch previously worked at OpenAI and Facebook’s AI Research Group.