Paradise Lost: The Child Murders At Robin Hood Hills / Revelations: Paradise Lost 2
I've only actually seen the second one, but it reprises the first one quite a lot. They're making a third as the appeals rumble on. The most amazing miscarriage of justice, and just a hugely powerful film, complete with cast of lunies.
Quite hard going in places, especially the graphic images of one of the murdered boy's mutilated genitals, and the bite marks on his face.
Too much to explain in one forum post, but one of those cases where you can't believe the policing of the incident and the witch hunt that ensued, plus the most blatant suspect (one of the boy's stepfather) who had once threatened a kid with a knife, was known to have hit his stepson, and had his own teeth removed once the bodies were discovered. Also, of the three boys, only one had his genitals mutilated and his face bitten - i.e. the more seriously deranged and "personal" attack, and therefore the focus of the attack - and he was this guy's stepson.