Paradise Lost 2: Revelations

Paradise Lost 2: Revelations is the sequel to the documentary film Paradise Lost: The Child Murders at Robin Hood Hills, a film in which three teeangers were accused of murdering three young boys in a satanic ritual. In Paradise Lost 2, Bruce Sinofsky[?] and Joe Berlinger[?] visit support groups for Damien Wayne Echols[?], sentenced to lethal injection in the first film, and revisit Mark Byers[?], who is facing gossip about his possible involvement with the murder of his son. Echols is appealing his sentence and his defense attorney notices what he believes to be bite marks in a photograph of the face of one of the victims; the prosecution argues that the marks are from a belt buckle and not teeth.

Warning: wikipedia contains spoilers

The three boys convicted in the first film are all tested and do not match the bite marks on the victim. The support groups for Echols want Byers to have his bitemark compared to the one on the photo, but Byers has had false teeth since four years after his son's murder. Byers takes a polygraph to "prove" his innocence but is on a variety of medication while taking it, including Xanax and Haldol; he "passes" the test.