Elon Musk played a big role in persuading Ilya Sutskever to join OpenAI as chief scientist in 2015. Now the Tesla CEO wants to know what he saw there that scared him so much.

Sutskever, whom Musk recently described as a "good human" with a "good heart"—and the "linchpin for OpenAI being successful"—served on the OpenAI board that fired CEO Sam Altman two Fridays ago; indeed, Sutskever informed Altman of his dismissal. Since then, however, the board has been revamped and Altman reinstated, with investors led by Microsoft pushing for the changes.