I don't know who done it (maybe the professor? I should re-read). But I'm guessing the firewood is the murder weapon.
So... The Professor, in the East Wing, by burning toxic Firewood?
Indeed the firewood is the murder weapon as the Raw shows
Heck yeahhhh, my Detective Conan history really coming in clutch
I love everyone in this story. It has amazing characters that are fun, likable and super cool. (They made the weaker female character the best character, like, the female characters are actually people it’s awesome) Art is reaaaallly good at setting the mood. And the story, is technically basic, but told soooo well. Love it!