Errol Morris’s ground-breaking role in pushing the boundaries of documentary cinema needs to be contextualized: when he was working on The Thin Blue Line, America was under the spell of direct cinema, which entailed a 'purist’ understanding of documentary as a set of rules such as hand-held camera, available light, observation without intervention etc; those rules had to be ticked in order to guarantee a filmmaker’s access to ’Truth’. Morris turned those rules on their head: he resorted to dramatic reenatments and allowed people to look into the camera, went for unusual camera angles and lighted his sets lavishly. Add to that Philip Glass’s score and the result is a documentary that is also an aesthetic experience – a sort of docu-noir or, as Morris describes it, a non-fiction Twilight Zone episode.

His background in history and philosophy, and his experience as a private investigator make Marris particularly appropriate to pursue the construction of truth in both the legal system and in documentary representation. Throughout his career, he will keep questioning the preconceptions about the default truth-value attached to things such as the archive footage in documentary or the eye-witness in the legal system, and will plant that seed of doubt about documentary being a construction rather than an objective document, which will later erupt in today’s elastic definitions of the genre.

The Thin Blue Line remains not only a remarkable demonstration of a new documentary aesthetic, but also the film that saved a wrongly convicted man when he was only three days from execution. And as fact always beats fiction, once released, the man sued Morris to gain back the rights to his story.