The evidence in question, Ross's journals and chat logs, were presented in trial and subject to rebuttal. He wasn't being tried for those crimes; those charges are still pending, but they were material to the case and the defense failed to dispute them. At the present moment, it is highly probable that he intended to have 6 people, including the innocent roomates of his targets, murdered.
And yes, I think I have a sort of psychological "stake" as you say in Ross' non-violence.