https://techcrunch.com/2018/08/01/facebook-loses-its-chief-security-officer-alex-stamos/

Alex Stamos, Facebook’s chief security officer since 2015, announced that he is leaving the company to take a position at Stanford University. The company has been shedding leadership over the last half a year largely owing to fallout from its response, or lack thereof, to the ongoing troubles relating to user data security and election interference on the social network.

“While I have greatly enjoyed this work, the time has come for me to move on from my position as Chief Security Officer at Facebook,” he wrote in a public Facebook post. “Starting in September, I will join Stanford University full-time as a teacher and researcher.”