In this episode, David retraces the last known steps of Glenrothes man Allan Bryant, and asks ‘how does someone go missing without a trace in the digital age?’

Dr Kirsty Bennett, from Leeds Beckett University, has a special interest in missing people. She talks to David about her research into the methods of locating missing people, as well as the missing continuum and the various reasons why people might disappear.

David is also joined in the studio by resident forensic scientist Helen Meadows. Helen talks to David about where to start when someone goes missing, and how to build up a picture of their movements. She also looks at the murder of Louise Tiffney in 2002. Even though Louise had not been found, she was presumed dead, and her son faced trial. He was given a 'not proven' verdict, but when her body was eventually discovered in a shallow grave in 2017, new evidence provided further links to the crime.

Professor Lorna Dawson, soil expert and head of forensics at the James Hutton Institute, tells David how she was tasked with gathering soil evidence and carrying out analysis in order to bring the accused back to trial under the double-jeopardy principle. Show less