Solution: MicroMacro 2.0

5×5 Murdoku case · Medium · murdokuonline.org

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

C1C2C3C4C5
R13Ch+CC4Bella
R2T+CCarolineTT
R31SCC2Dittbert
R4CCApo
R5OppiChChTT

Where everybody stood