“I can confirm that it was suicide and that he has been depressed for a short period of time,” Johar Bendjelloul told a newspaper.

Searching for Sugar Man won the Oscar for best documentary in 2013.

The low-budget film told the story of two South Africans searching for their music hero, 1970s American singer Sixto Rodriguez.

Bootleg copies of the singer’s album Cold Fact had been an unofficial soundtrack to youth protests against apartheid in the 70s and 80s, but it was believed he had died in a bizarre onstage accident.

He was eventually found in Detroit, working on a building site, and persuaded to play a series of triumphant gigs in South Africa, where he was treated like a hero.

Rodriguez told Expressen newspaper: “Malik was a fantastic person. He was both unique and very friendly.”

And Simon Chinn, the British producer of Searching for Sugar Man, said: “It seems so unbelievable. He had everything to live for.”

Chinn told the Associated Press that he had seen Bendjelloul in London two weeks ago.

Searching for Sugar Man was almost abandoned mid-production, when Bendjelloul ran out of funds. He persevered and pieced the film together over five years, even shooting some sequences on an iPhone.

“It was an extremely primitive production,” he said. “It was done on my kitchen table in my apartment in Stockholm without any money at all,” said Benjelloul after its release. He was determined to complete the project, he added, because “it is the best story I have ever heard in my life, and I think I ever will hear”.

The film went on to make $3.6m at the US box office.

Bendjelloul was born in the town of Ystad in southern Sweden, about 35 miles east of Malmo. As a child, he acted in the TV series Ebba and Didrik, before studying journalism and media production at the Linnaeus University of Kalmar. He later worked as a reporter for Swedish public broadcaster SVT, but resigned to travel the world. During that trip, he stumbled across the story for Searching for Sugar Man.

He had also directed television documentaries about singers Elton John, Rod Stewart, Bjork and German electronic music pioneers Kraftwerk.