Someone could feasibly approach one of these third party vendors, King says, and pay for a package of location data, which might include when a user logged in and out, their approximate locations, and their phone’s static ID number (a unique string of numbers assigned to each mobile device). These packages can feature users of specific apps, like dating apps, explains Ben Zhao, a professor of computer science at the University of Chicago.
The issue, King explains, is that if you wanted to find the static ID number of a particular individual’s phone, and knew identifying factors like where they lived, worked, and traveled, you could parse through all of the location data to figure out which static ID number belongs to that person.
It appears The Pillar did just this. In its report, The Pillar said it “correlated a unique mobile device to Burrill when it was used consistently from 2018 until at least 2020 from the USCCB staff residence and headquarters, from meetings at which Burrill was in attendance, and was also used on numerous occasions at Burrill’s family lake house, near the residences of Burrill’s family members, and at a Wisconsin apartment in Burrill’s hometown, at which Burrill himself has been listed as a resident.”