A new Channel 5 documentary on the murder of Holly Wells and Jessica Chapman will air tonight.
The Soham Murders will cover the events leading up to and after the murder of the 10-year-old friends, alongside the motivations and history of their killer, Ian Huntley.
Episode one charts the first 14 days of the girls' disappearance after they went missing in August 2002.
READ MORE: The Soham murders: What happened to Holly and Jessica
The second episode airs tomorrow night and will cover Huntley's downfall as evidence emerges and the truth is revealed to the world.
Huntley worked as a caretaker in a nearby secondary school, Soham Village College. During his time there he became engaged to Maxine Carr, who was employed as a teaching assistant in Holly and Jessica's school.
Originally a participant in search parties for the missing girls, Huntley quickly became a prime suspect in their disappearance.
Former Special Police Constable Sharon Gilbert is interviewed as part of the documentary and revealed she became suspicious of Huntley after he quizzed police on the investigation.
She said: "We were tasked to go to Soham College, and Ian Huntley approached the vehicle and lounged over the hinge section of the door.
"He was very relaxed in his talking, he wasn't nervous in any way shape or form.
"Quite early in the conversation he said to me, 'how long said does DNA evidence last?'
"I said 'indefinitely, they've used it on the Russian Tsar family and woolly mammoths I believe'.
"It was like he was looking at you but through you, like you're not there."
The officer requested the authorities look into Huntley following the question - and he was found guilty of the two murders in 2003.
Huntley was 29 years old at the time and sentenced to a minimum of 40 years in prison.
The child killer was admitted to hospital in 2007 after he took an overdose of prescription medication while on suicide watch at Wakefield high security prison.
It was the third such incident involving Huntley since he was imprisoned and officers found him still conscious before taking him to an undisclosed hospital.
Huntley is still serving his sentence at HMP Frankland in Durham.
The Soham Murders airs tonight at 9pm on Channel 5
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