A scientist's breakthrough helps a detective track down a murderer.

It's 1984, and Dr Alec Jeffreys unlocks a technique to read every individual's DNA fingerprint, while DCS David Baker leads the search for the murderer of a schoolgirl.

Code of a Killer

How groundbreaking DNA science helped solve a murder case - a true story

John Simm and David Threlfall star in this groundbreaking crime drama based on a true story. A scientist and a detective are both intent on solving a grisly Leicester murder case.

code-of-a-killer

DCS Baker proposes an extraordinary idea to catch the killer.

With his innocence proved by Dr Jeffreys' DNA test, the teenage suspect is released to a storm of controversy. Plus, DCS Baker proposes an extraordinary idea to catch the killer.

Code of a Killer

Code of a Killer

Series 1

Episode 1

Episode 2