Is the book any good, aside from having been written by a murderer? After all, Anne Perry committed premeditated murder (with a brick) on a friend's mother and later became a successful author, William Burroughs shot and killed his wife, and Norman Mailer stabbed and nearly killed his wife. Their work outlives them. Perhaps Mrs Richins's book is the greatest book ever written to help children cope with bereavement and she will be remembered forever for her contribution to literature.
Or perhaps not.