Gordon Corera travels to Stockholm to investigate the assassination of Swedish prime minister Olof Palme. He begins with newly-unearthed documents written by writer Stieg Larsson.

In the first of the new series of Document, Gordon Corera travels to Stockholm to investigate theories about the 1986 assassination of Swedish Prime Minister Olof Palme.

He begins with newly-discovered documents written by the late novelist and investigator of the far-right, Stieg Larsson.

But the trail leads him to the role of various secret services, to questions about elements of the Stockholm police, to South African dirty tricks, and ultimately back to Britain, where he makes a surprising discovery.

Producer: Phil Tinline.