Last week, it was revealed that Facebook and other major tech companies allowed a controversial surveillance tool to use data from social media to track protesters around the United States. Once it was revealed what Geofeedia, the tool in question, was doing, Facebook and the other sites cut off access to it. There were also questions raised as to whether Facebook even knew what Geofeedia was doing with its user data. However, according to a new report from The Verge, Facebook used Geofeedia itself for corporate security.

In a 2015 blog post, Geofeedia bragged about how it was used to catch an intruder in the office of a major social media company’s CEO.

“A major social media company used Geofeedia in its GSOC [Global Security Operations Center] to identify a trespasser in its CEO’s office,” the post read. “The trespasser had been taking photographs in the office and uploading them via his mobile phone while in the office. The security team saw the post, and were able to confront trespasser in the office minutes after the photo was posted.”

Now, two anonymous former Geofeedia employees have told The Verge that the CEO was none other than Mark Zuckerberg.

This report raises a few important questions. First of all, did Facebook use Geofeedia on its entire campus and track its own employees? And since the site had a prior relationship with Geofeedia, did it know how the tool was handling its user’s data all along? We probably won’t ever get a clear answer, but the revelation only adds to the mistrust many already feel for the site’s handling of private information.