It’s clearly his data, as evidenced by the iMessage content that’s been released. There’s always a possibility it’s stolen data laundered through the computer shop, but that depends on the shop owner turning it over to somebody. Maybe he was in on it, but if not it’s a lot of coincidence that has to go just right to get the data out there. At that point you may as well create a torrent with the disk image and push it out there for everyone to see.