Joshua Oppenheimer’s documentary wins jury award at the Sheffield festival.

The Act of Killing has won the Special Jury Award at the 20th Sheffield Doc/Fest.

The film, directed by Joshua Oppenheimer, features former Indonesian death squad leaders reenacting their real-life mass-killings.

Producer and jury spokesperson Krishan Arora said: “From its mystical beginning, this film presented to us the celebratory narrative inside people’s heads while they are committing unspeakable acts.

“Despite its uncomfortable length, it revealed a reality of genocide in which we are all complicit. The film leaves you asking more questions than it provides answers and is an important piece of cinema.

A special mention was given to Xu Huijing’s Mothers, which centres on a village in northern China and the impact of the state-enforced birth control policy.

Prizes were handed out at a ceremony this morning on the final day of Sheffield Doc/Fest (June 12-16).

The Inspiration Award went to BBC Storyille editor Nick Fraser, who said: “The greatest docs are oddly innocent, too - as if they and we who watch them are seeing things for the first time”.

The Youth Jury Award was handed to Roger Ross Williams’ God Loves Uganda, which focusses on the impact of US evangelicals in the African country.

The Innovation Award was picked up by Alma, a Tale of Violence, directed by Miquel Dewever-Plana and Isabelle Fougère.

Centred on a teenager who killed someone to join a Guatemalan gang, Alma’s confession is told through the iPad, with viewers invited to stroke her face to navigate the story.

The Sheffield Green Award was won by Robet Stone’s Pandora’s Promise while a special mention went to Michal Marczak’s Fuck For Forest.

The Student Doc Award was prsented to Marc Williamson’s Boys, which follows the struggles of two pupils over a term in a UK boarding school for boys with emotional and behavioural disorders.

The Short Doc Award was picked up by Josh Izenberg’s Slomo, about a rollerblader in Los Angeles.

The inaugural Tim Hetherington Award, celebrating the photojournalist who died while covering the Libyan civil war in 2011, was won by Jehane Noujaim’s The Square, which included a £1,000 cash prize.

The film was selected by a jury incluing Hetherington’s mother, Judith, and representatives from Doc/Fest and Dogwoof, the UK distributor of Hetherington’s Oscar-winning Restrepo.

The EDA prize for best female-director film, awarded by the Alliance of Women Film Journalists, went to Rafae Solar Mama, directed by Mona Eldaief and Jehane Noujaim.

The EDA also presented a special award for outstanding achievement to Sheffield Doc/Fest director Heather Croall who, “works tirelessly to boost documentary film and open opportunities for women filmmakers”.