In this unique investigation, serial killer Charles Sobhraj, known as 'The Serpent', agrees to a series of psychological and criminal interrogations concerning murders that he's never been tried for, as experts try to get to the truth.

Former detective Jackie Malton steps up her investigation into serial killer Charles Sobhraj, focusing on five murders committed in Thailand in the 1970s. Sobhraj once confessed to the killings in taped interviews, but has since withdrawn this.

The detectives work to collate all the existing evidence about Sobhraj and gear up for their final interrogations. And forensic psychologist Paul Britton makes his full assessment as to whether Sobhraj remains a dangerous man.