The Empty House

When Peter checks on his 82-year-old father at home one morning as normal, he finds the house empty. Suffering from advancing dementia, Archie has vanished - leaving no sign of where he might be.

As Sergeant Barry Evans explains:

"You're trying to work out why has he gone missing: is it a physicality thing, he's slipped, he's fallen, he's hurt himself and we need to find him because he needs our assistance medically... Is it a case of he's taken a walk that's too far, that he's bewildered, he doesn't know what to do? Or alternatively, possibly, that somebody has taken advantage of his vulnerabilities, because he's not quite aware of what's going on."

PC Geoff Moore's job is to get as much information as he can from the son Peter: "Family are hurting and you've got to be mindful of emotions but at the same time I've got a short space of time to gather as much information as I can."

As an ex-paratrooper, Archie has been physically fit all his life and has been struggling to accept his increasing fragility. Dementia sufferers are known to travel vast distances when they disappear, and a full-scale land and air search is launched to find Archie.

But as hours tick by without so much as a single confirmed sighting, and a neighbour comes forward with CCTV of potentially suspicious activity at Archie's home address, the police begin to suspect foul play.