Just for context: This is relativly new in Germany. In 2017 there was a change which has as consequences
- witnesses _have to_ appear in person if requested (by police or DA)
- witnesses _have to_ make statements regarding the case at hand
This is quite a nice tool if you lack moral. You might request the suspect to appear as a witness and try to leverage the new requirements to make the suspect reveal damaging information.
Maybe this was the reason that Germany was mentioned before.
