Key legal question
When does the three-week deadline under § 47 StPO begin after a detained person is taken over from another canton?
Extracted holding
The deadline begins with the physical transfer of the detainee, but no earlier than receipt of any formal transfer order from the former canton.
Extracted reasoning
Physical transfer marks the moment when procedural responsibility passes and avoids uncertainty over competence. The receiving investigating judge may need time to review the file and should file a timely detention-extension request if continued custody appears necessary.