A shortened version of the gundrill was accurately identified by the fictional programme's forensic pathologist Dr Thomas Chamberlin (played by Richard Lintern) as a specialist engineering tool used for drilling deep holes in metal. From his statement the police were able to narrow down the list of suspects to former apprentices at an engineering company.
Commented Guy Mollart, managing director of deephole drilling and gundrill specialist Mollart Engineering: "As the pathologist examined the victims he was originally mystified by the unusual penetration marks on their necks. He did exceptionally well in linking the marks to such specialist drill points found on a gundrill. But he did not realise that one of the most important features of the tool was the production of very straight and much deeper holes than he was finding on his corpses!"
