Solution: Stille Wasser

6×6 Murdoku case · Easy · murdokuonline.org

Dalia did it — the only suspect in the room with the victim, outlined in red below.

C1C2C3C4C5C6
R13GBernd4TCT
R2CyrusTCT
R3CElsaTCa
R41TrTr2Viktor
R5TrDaliaB
R6TrAnna

Where everybody stood