Apparently, this was a decision made at the top by Marissa Mayer, and pissed off the company’s top security guy, Alex Stamos (who is awesome and a big supporter of end-to-end encryption) leading him to leave the company (and move to Facebook, where he is currently).

According to the two former employees, Yahoo Chief Executive Marissa Mayer’s decision to obey the directive roiled some senior executives and led to the June 2015 departure of Chief Information Security Officer Alex Stamos, who now holds the top security job at Facebook Inc.”Yahoo is a law abiding company, and complies with the laws of the United States,” the company said in a brief statement in response to Reuters questions about the demand. Yahoo declined any further comment.

Of course, this comes out less than a week after the NY Times had a big report on how Mayer de-prioritized security, despite having built up a great team of computer security experts called “The Paranoids.” But, Mayer apparently downplayed or blocked their efforts, leading many to go elsewhere. And now we find out that Yahoo agreed to create this special software for scanning all emails for certain phrases or keywords. Bizarrely, this new report notes that Mayer gave the task of writing this software not to the security team, but to email engineers, leaving the security team in the dark, until they discovered it, thinking it was malware: