You caught us red-handed! We didn't deliver the solution as promised. Please forgive us for dropping the ball! Our little theatre family can sometimes be quite busy (we know, we know...it's no excuse...but it was true!).
In any case, in The Case of the Missing Ruby, it was none other than HILARY!! She was the only one who knew the method of slaughter (a crossbow), and that detail hadn't been revealed yet! May she rot in literary prison!
Thanks to all who played along with us!