If nothing else, it seems pretty silly to have the stolen source accessible from the new work computer. That's just asking for the ruse to be detected too easily (automated backups, virus scanning, etc which could fingerprint the data). Keep the illicit goods on an air-gapped, encrypted, personal computer that you can reference as required.

As far as I know, they were never able to find the Waymo files that Anthony Levandowski stole, because he was at least crafty enough to not load everything directly onto Uber hardware.