I personally know of many prisoners who were on remand at risk of being convicted of murder, rather than manslaughter, simply because witnesses had heard them make threats weeks or days before the actual time when there was a confrontation where the other party lost their lives, and guilt or innocence depended on the words uttered on these other occasions, weeks or days beforehand?
I do not see any difference here, in this example, where Sheila told Ann Eaton, "ALL PEOPLE ARE BAD AND SHOULD BE KILLED"...
These words/threats were/are important in the context of this case, and should have been spoken out about, not suppressed and kept secret, since an innocent mans life hung in the balance