BBC One - Expert Witness, Series 4

Cracking the Killer's Code

4/15 Police turn to a forensic linguist to crack the code of a gang using a secret language.

1/15 The murderer of Sarah Payne is linked to the crime by a forensic pollen expert.

3/15 When a body is found in a wheelie bin, an expert tracks the suspects’ mobile phones.

5/15 Untying the knot in a dressing gown cord used to murder a woman finally nails her killer.

6/15 An intelligence analyst tracks the killers of a man stabbed to death in his own home.

8/15 After a body is found in a burning flat, a blood spatter analyst looks for evidence.

9/15 When a teen is fatally stabbed, an expert analyses the wounds to shed light on the attack.

10/15 An image analyst helps detectives unmask the killer of a young girl in Liverpool.

11/15 A mother and son vanish in 1976. Forty years on, a blood analyst helps to find the killer.

12/15 Rachel Nickell’s murder was unsolved until DNA technology finally identified her killer.