Washington-based North Korea watchdog group 38 North published a report on Monday suggesting that North Korean animators may have been hired by Western firms to work on their projects in defiance of international sanctions.

One of the projects mentioned by the report was the popular Amazon Prime superhero series Invincible.

The report was based on files procured by 38 North and cybersecurity firm Mandiant from a North Korean cloud server late last year. The server, discovered by a Boston-area amateur sleuth named Nick Roy, was seemingly abandoned but still accessible. Its security software was not properly configured, allowing anyone to view its contents without a password.