A Milkshake in the Air

Late on the night of 28 November 1976, a Dallas police officer named Robert Wood stopped a car that was driving without its headlights on. As he walked up to the driver's side he was shot and killed. His partner, Teresa Turko, fired at the car as it drove away.

A month later police arrested David Ray Harris, a sixteen-year-old from Vidor, Texas, who had stolen the car and had been boasting that he had killed a policeman. Harris said he had been in the car, but that the man driving and shooting was a hitchhiker he had picked up that day: Randall Dale Adams, who had come to Texas from Ohio looking for work. Adams agreed that he had spent the day with Harris, but said Harris had dropped him at his motel hours before the shooting.

The case came down to a choice between a juvenile who could not be sentenced to death and an adult who could. Adams was tried in 1977, convicted largely on Harris's testimony and that of witnesses who said they had seen him at the wheel as they drove past, and sentenced to death. In 1980 the Supreme Court overturned the sentence on a point about jury selection, and it was commuted to life.

Errol Morris came to the case sideways. He was researching a psychiatrist who regularly testified for the prosecution at the sentencing stage of Texas capital trials, and who had testified against Adams. Adams was one of the defendants Morris met through that work, and his story pulled Morris away from the film he had planned.

The Thin Blue Line, released in 1988, does something that by the usual rules a documentary should not do. It re-enacts the crime. And it re-enacts it repeatedly, with actors, in stylised fragments: headlights, a gun, a milkshake turning through the air in slow motion, all set to a hypnotic score by Philip Glass.

The trick is in what those re-enactments are attached to. None of them is offered as what happened. Each stages one account: Harris's version, the partner's, the passing witnesses'. Where was the partner when the shots were fired? Could someone in a passing car have seen the driver's face? Who was at the wheel? Staged side by side, the accounts stop corroborating each other and start contradicting, and the audience can watch them do it. Fiction's techniques are being used to display testimony, and displaying it is what makes it testable.

The interviews do the rest. The witnesses who placed Adams at the wheel come across, in their own words, as people with reasons to say what they said. And Harris, by then in prison for a later crime, talks to Morris at length and edges, interview by interview, towards the truth. The last of those interviews is not filmed at all. It is heard as audio from a tape recorder, and in it Harris all but admits that Adams was innocent. The decisive evidence in this most stylised of films is its least cinematic moment.

The film drew attention to the case, new hearings followed, and in March 1989 the Texas Court of Criminal Appeals overturned the conviction. Prosecutors declined to try Adams again, and he was freed after more than twelve years in prison. Harris was never tried for Wood's murder. He was executed in 2004 for a different killing.

The usual rule says reconstruction is where documentary stops being evidence and starts being drama. This film is the strongest case against the rule, and it is worth being precise about why, because its grammar was taken up so widely afterwards. Interviews to camera, cut against moody reconstruction under an insistent score, became the standard look of true-crime television. What was mostly not taken up was the discipline. A reconstruction that illustrates the police theory, or the narrator's conclusion, while a voice explains what happened, borrows the authority of The Thin Blue Line and does the opposite of what it did. Morris's re-enactments were claims, labelled and staged so they could be compared. Most of the ones that followed are conclusions dressed as evidence.

Re-enactment is neither honest nor dishonest in itself. It is honest when the film makes clear whose claim each image shows, and leaves the audience in a position to doubt it.