This individual flew for Garuda as an F/O but then "spread his wings" and became a "false" Captain, flying for airlines across Europe and beyond, including Eurowings
https://www.aerotelegraph.com/sicher...europa/flmgjqe
(The article is in German, so translation will be required if necessary)
How did he manage to escape the licence and qualifications checks?
Just on a curiosity basis, how often does this actually happen?