Susanna Reid documentary on Peterborough serial killer Joanne Dennehy to broadcast tonight

On Good Friday 2013, Joanne Dennehy killed John Chapman and Kevin Lee. She had killed Polish national Lukasz Slaboszewski about 10 days before. She dumped the bodies of the three men in countryside around Peterborough, with the help of accomplices, before going on the run, and seriously injuring two other men in Hereford.

In 2014 she was told she would never be released from prison - only the third woman in British history to be given a whole life sentence.

Tonight, six years after the brutal knife murders, Susanna Reid will present a documentary about Dennehy, speaking to detectives who worked on the terrifying case, and people who knew the killer.

“She doesn’t come from a background where you could draw a direct link from something terrible happening to her and her becoming a terrible person,” Ms Reid said.

“She came from a stable, decent family home and was well looked after.

“Her family said butter wouldn’t melt in her mouth.

“When there is not an obvious explanation for why someone has become a serial killer that makes the detective story more fascinating, doesn’t it?

“It’s not just a tabloid fascination with women who are able to do these things.

“Even the police officer who was investigating the case, when he came across the first body of Kevin Lee in the ditch, his assumption was that the person responsible was going to be a man, because you needed the strength to dispose of the body.

“But also the humiliating way this poor man had been left in the ditch. He said he never anticipated it was going to be a woman who could do this.

“’How could a women do this?’ is a question that comes up over and over again.”

Ms Reid herself became fascinated by Dennehy while working on the programme and describes her as an “abhorrent, horrific, compelling, magnetic character”.

She added: “Her family wrote us a letter about her, saying she was a bookworm when she was at school, she was a good girl, she came from a decent background, happy family, given all the advantages she could possibly want.

“How did she turn into a woman who could brazenly swagger into a police station at the age of 30, boast about the fact she thought five people were dead as a result of her actions, flirt with police officers and show off about being a serial killer?”

“We had exclusive access to the full custody tapes, when she’s arrested after being caught on the run and the police know that there are two men fighting for their lives.

“Eventually it emerges that she has already killed three people.

“She is standing in police custody and you would think she would be at least a little bit nervous, at least a little bit concerned for her future and yet she is boasting ‘attempted murder and murder is nothing. It’s like going down for a Sunday roast. Easy’.

“She starts flirting with the police officers, trying to charm them and win them over, and you can see they are reluctantly drawn into her web. She’s obviously a really compelling character. She starts playing with her hair.

“Her barrister described her and says he wondered whether he had got the wrong cell, when he eventually goes in to meet her for the first time.

“Normally he would expect someone accused of these awful crimes, who is facing a future in prison never to be released, to be a little bit wary and on the back foot. She wasn’t.

“He said she just seemed to be confident, charismatic, cooperative and she had the type of personality he was drawn to.”

Joanne Dennehy: Serial Killer is on ITV at 9pm on Thursday, April 18.

More: Joanne Denney - a Timeline, with links to The Peterborough Telegraph’s coverage of the case