Witness of Truth: The Railway Murders is a British television docudrama, first broadcast on 11 December 2001, that dramatises the crimes committed by John Duffy and David Mulcahy, commonly known as the Railway Rapists or Railway Killers. The film, produced and directed by Bren Simson, is narrated by Lindsay Duncan, who provides additional details of the crimes, some of which are not dramatised in the film. Huw Higginson and Nicholas Marchie were cast as Mulcahy and Duffy respectively, with Steve Chaplin and Tat Whalley portraying teenage versions of the pair.

Adelene Alani acted as executive producer. Other notable cast members include Mark Spalding, who co-starred alongside Higginson in The Bill in 1995, Caroline Woodruff, Joanna Monro and Robert Swann. The film broadcast at 22:35; subsequently no viewing figures for the programme were recorded by BARB. The film has never been repeated and remains unreleased on VHS and DVD.