Umineko. The Culprit?

Sooo I've been wondering has anyone found out who the culprit is or has made a 50% concrete guess as to who it is?. I'm not asking for spoilers to the VN just wondering how many detectives we got on the forum. Thought I might as well make this since The last episode is being translated as we speak.

Sooooo who do you think dunnit and why?

Yes but who is the mastermind? Can you answer that?