/jp/ - Otaku Culture

I feel like Krauss is suspicious, but it's probably a red herring.
He was the only one to hear the fight in the study. The first thing he did after that was call the servants over to get the door unlocked; By the time our brave and intelligent detective arrived, the closed room was already destroyed.

I don't have a theory yet, so I'll just try these obvious ones.
/BLUE/ Kinzo was dead before Krauss arrived. The struggle in his room took place long before the corpse was discovered.
/BLUE/ The envelopes for the letters were poisoned. He was licking one of them to seal it up, causing the poison to kill him.
/BLUE/ Kinzo was killed after the door was unlocked, but before Battler arrived.