John Binns, a U.S. citizen who has been incarcerated in Turkey, is linked to the massive data breach of metadata belonging to nearly all of AT&T’s customers that the telecommunications giant announced on Friday, three sources independently told 404 Media.

The breach, in which hackers stole call and text records from a third-party cloud service provider used by AT&T, is one of the most significant in recent history, with the data showing what numbers AT&T customers interacted with across a several month period in 2022. 404 Media has also seen a subset of the data, giving greater insight into the highly sensitive nature of the stolen information.