Question juridique clé
Whether the public-law appeal against the cantonal detention decision was admissible
Solution extraite
The appeal was admissible in principle, but only against the final cantonal decision; challenges to earlier cantonal rulings were inadmissible.
Motifs extraits
The Federal Supreme Court reviews admissibility ex officio. Only the last cantonal decision can be attacked when the cantonal instance has full review powers, and the cassatory nature of the remedy leaves the requested immediate release unresolved.