[2016-02-04: I hate to do it, but I changed my score from a 4 to a 3, after trying to watch a few more episodes. This series is just not for me. It seems that, during the first episode, they smartly used more reenactments early, and then showed the interviews mostly at the end, where lately, interviews are interspersed throughout, which kills some suspense.]
Even though I watch way too much true-crime TV, I don't know exactly how the parole system works, perhaps luckily. I would imagine that the parole board can and may use any information at their disposal, including crime-scene photos, evidence, and court transcripts. But it very well might be the case that they can watch post-sentencing interviews as well, or use any other public information available. At least that would be my guess.
As an example, although the laws are slightly different in Canada, Paul Bernardo applied for day parole in Toronto. For anyone not familiar with the case, he killed three girls, with the help of his ex-wife who was surprisingly paroled herself. But he just published an e-book with violent themes on this site -- an e-book that was quickly removed, from the reading I've done -- but supposedly, just writing the book will "hurt his chances" at parole. Not that he ever really had a chance anyways, as jailmen have said, "Bernardo will only leave prison in a pine box." I know that he has done at least one interview from prison, and that is still available on a streaming site for your "entertainment."
And for this reason, if I were an attorney for a defendant in a murder case, I would tell that client to keep his mouth shut. No ifs, and, or buts. Even if that client's been found guilty -- ESPECIALLY if he's found guilty. After all, as long as there's some doubt, there's always a chance for appeal or for parole. But once you start talking, most of the doubt vanishes like, oh, a pretty cheerleader on a dark Oklahoma night.
But with "Shadow of Doubt" (why not "Shadow of a Doubt?") the viewer will not only get insight from the police and the family of victims, but will get insight from the perpetrators -- "perps" in police lingo, I believe -- as well. At least with Season 1, Episode 1. Without giving much away, towards the end of that episode, the perps give their side of the story. I won't tell you the location of where they're interviewed either, since that might be a bit of a spoiler.
So this is good for the viewer and probably bad for the perps. And probably really bad for the attorney, and it might even keep him up nights. But this show seems willing to show the dark side of everyone here, including the victim, and so the viewer might be more receptive to understand why at least the crime happened in the first place. (With the first episode, lets just say that I wasn't exactly sympathetic to the perps. But I did feel that I understood their perspectives after watching.)
Regardless of how you feel about criminals giving interviews, there is little doubt that this series has at least a shot. After all, how often do you truly get all sides of the story? Not too often, unless you watch "Shadow of Doubt," from my experience.