ITV has revealed the first trailer for John Simm and David Threlfall’s Code of a Killer, from the makers of Line of Duty.

The two-part drama is based on the true story of Alec Jeffreys’ discovery of DNA fingerprinting and its first use by Detective Chief Superintendent David Baker in catching a double murderer.

Code of a Killer begins at 9pm on Monday 6 April on ITV.

> Order Code of a Killer on DVD on Amazon.

Shameless star David Threlfall plays Baker, who between 1983 and 1987 headed up the investigation into the brutal murders of two Leicestershire schoolgirls, Lynda Mann and Dawn Ashworth.

John Simm (Life on Mars, Doctor Who) plays Dr Alec Jeffreys, a scientist at Leicester University who invented a remarkable technique to read each individual’s unique DNA fingerprint in September 1984.

Watch the trailer…

The official synopsis reads: “When a local teenager admitted to one of the murders but not the other, Baker asked Jeffreys to analyse the DNA evidence left at the crime scenes. Both men were shocked to discover that the teenager was innocent, his confession false. DCS Baker then took the extraordinarily brave step to launch the world’s first ever DNA manhunt, testing over five thousand local men to track down the killer.”

Code of a Killer‘s cast also includes Lorcan Cranitch (Penny Dreadful), Robert Glenister (Spooks), Siobhan Redmond (Between The Lines), Anna Madeley (Sense & Sensibility), Dorothy Atkinson (Call the Midwife), Andrew Tiernan (The Driver), Jaz Deol (Restless Dust), Hannah Walters (Whitechapel), Lydia Rose Bewley (The Inbetweeners) and Ged Simons (Downton Abbey).

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