I will freely admit, one thing about this quest bothered me the first time i did it.
It only took me 3 pieces of evidence to figure out who did it. However, in my search i missed one or two of the other clues. Because of this, when i went to make my accusation the correct dialogue choices werent there and i was forced into a bad ending. Always sucks in "mysteries" like this when you're smarter then your character and you fail something because they needed more then you did to reach the right conclusion.