Chris Lattner, who left Apple in January to become Tesla's head of autopilot software in January is now leaving the carmaker.
"Turns out that Tesla isn't a good fit for me after all," he said in a Twitter post on Tuesday night. "I'm interested to hear about interesting roles for a seasoned engineering leader!"
Lattner had headed up Apple's development of the Swift programming language.
Meanwhile, TechCrunch reports that Tesla has hired computer vision expert Andrej Karpathy for a key role on the autopilot team. Karpathy was most recently at artificial intelligence research group OpenAI, which has backing from, among others, Tesla CEO Elon Musk.