This is a gem. As a Film Four production - the anticipated quality was indeed delivered. Shot with great style that reminded me some Errol Morris films, well arranged and simply gripping. It's long yet horrifying to the point it's excruciating. We know something bad happened (one can guess by the lack of participation of a person in the interviews) but we are compelled to see it, a bit like a car accident in slow motion. The story spans most conceivable aspects and unlike some documentaries did not try and refrain from showing the grimmer sides of the stories, as also dealing with the guilt of the people Don left behind him, wondering why they didn't stop him in time. It took me a few hours to get out of the melancholy that gripped me after seeing this very-well made documentary.