Paradise Lost 3 is the most factual one of the trilogy.

Some people think this documentary is biased and still believe they are guilty. I just finished watching PL 3 and of all of the docs, it is the one that shows there were mistakes, contradictions and incompetency on the original trial. It has the benefit of hindsight and looks at the cold hard facts and new evidence not discovered when PL aired in 1996.

So, if you already made your mind about their guilt, you should watch Paradise Lost 3. Skip 2. It adds nothing to the story of the case.