Alex Stamos joined Facebook as chief information security officer in June 2015 and has been a staunch proponent of uncovering and disclosing how Russian Federation used the social network to influence the USA presidential election. Mr Stamos is the first high-profile executive to depart since questions arose about how the company's platform may have been misused by foreign actors during the 2016 U.S. presidential election.
"It's true that my role did change", he wrote shortly after the Times story broke. Early on in his Facebook career, Stamos reportedly faced dismay from COO Sheryl Sandberg over how proactive the platform should be policing itself.
Stamos took to Twitter later Monday evening to clarify that he had not left the company, but did not say whether he planned to leave.
Unlike other top executives at the company, the Times reported, Stamos has always been an advocate for investigating Russian propaganda and other "disinformation" spread on Facebook.
He raised the alarm inside Facebook about Russian activity a month after the 2016 election by sending a memo to Chief Executive Mark Zuckerberg and other top officials saying that Russia had run an information operation campaign on the platform, The Wall Street Journal reported this month. "I'm now spending more time exploring emerging security risks and working on election security".
Alex Stamos, Facebook's chief information security officer, will shift roles at the company.More news: MS boy, 9, shoots sister, 13, over video game controller, police say
Likewise, Facebook's statement entirely ignored questions about the August date.
A well-known figure in the world of cybersecurity, Stamos' day-to-day responsibilities were assigned to others in December - prompting him to make plans to leave, the Times said.
Facebook's global policy vice president Joel Kaplan said in February that the company had been working with the Federal Bureau of Investigation, the Department of Homeland Security and the special counsel probing claims of Russia's collusion with the Trump campaign. He was security chief at Yahoo during the largest security breach in history.
Stamos is famous for publicly questioning National Security Agency Director Adm. Mike Rogers at a conference in Washington in 2015.
When asked to comment, Facebook referred BuzzFeed News to Stamos' tweet. The tweets said the situation, in which the firm accessed information from millions of Facebook accounts, wasn't a data breach or a leak.