Kernrechtsfrage
Whether the cantonal authorities violated the duty to establish the material truth by not hearing eyewitness D.
Extrahierter Entscheid
Yes. The available eyewitness should have been examined as a witness because his account was central to reconstructing the killing.
Extrahierte Begründung
The file contained an unbroken, direct account from an uninvolved eyewitness who had observed the event. Refusing to hear him led to speculative findings and prevented a reliable assessment of self-defence and putative self-defence.