Stranger things have happened. Though now it's beginning to sound like a mass vendetta even if he is presumed innocent,for it's the power of the public that'll keep him where he is and NOT so much the legal system. Let's face it,it only needs the usual war-cry from the relatives saying that " they all fear for their lives " and that'll be the end of any more thoughts of appealing, that would be my reason for his continued incarceration even if his innocence is proven.
Too many people have too much to lose otherwise !!
I would guess that any author would hopefully spend a lot of time on research and should go in open minded and I think the timings are more to do with the 30 year anniversary than anything else .
If what has been inferred about the appeal is correct - then the book will be irrelevant. But if it contains new evidence that is valid then it should be used through the correct channels.