Britain’s youngest double murderers were publicly named after a High Court ruling earlier this month.
Kim Edwards was just 14 when she and her boyfriend Lucas Markham, also 14, killed her mother Elizabeth, 49, and younger sister Katie, 13.
The mother and daughter were found with their throats cut in their beds in Spalding, Lincolnshire, on April 15 last year. A court heard the motivation for the murders was Kim’s belief her mother favoured her younger sister and her attempts to end her relationship with Lucas.
Kim and Lucas were originally jailed for at least 20 years each in November last year, but judges reduced the sentences to 17 and a half years.
Now Channel 5 has exclusive audio extracts of Lucas’s confession as he calmly told officers what happened that night.
In extracts featured on Murdered by my Daughter, which will air on Monday at 9pm, the teenage boy said: “I went into her mum’s room and stabbed her in the neck while she was asleep on her side and smothered her face with a pillow.
“And after I knew she had gone, I went into Katie’s room – which is the same room as Kim’s – and I thought I stabbed her, but… I thought I stabbed her, but I’m not a hundred per cent sure – it was, like, her on a mattress and then I smothered her face with a pillow too.”
Lucas admitted killing the dinner lady and then murdering Katie because he feared she would call the police. When asked to confirm if that was the only reason, he casually confirms: “Pretty much.”
After having a bath to wash off the blood, the teenage sweethearts ate tea cakes and ice cream while watching vampire movie Twilight before having sex.
Detective Superintendent Martin Holvey of Lincolnshire Police, who led the investigation, told the programme that neither Lucas nor Kim, both now 15, showed any remorse during questioning by police.
He added: “You actually recount the story to your team and everyone sits there - hardened detectives - and think, I can’t believe what you’re hearing.
“You know, over 30 years as a cop, you look at this case and there’s nothing that rivals it that I’ve come across.
“A really brutal, chilling, cold and callous act that was carried out by these two children on two defenceless victims.”
Police had already released part of the audio recording of Kim’s confession, in which she admits going into her mother’s bedroom after Lucas had killed her – to check that he was okay.
Asked by the police how she felt immediately after her mother and sister had been killed, Kim replied: “I was okay with it. Just the fact that it happened so quickly that, like, gave me peace of mind cos like, you know, it wasn’t like torture or anything.”
Elizabeth’s partner, lorry driver Graham Green, has since described Kim as “another Myra Hindley as far as I’m concerned.”
He added: “She should be never, never let out, ever. She’s…trying to put, trying to put herself on the map. She’s trying to run before she can walk. Look what I did, I’m the big – I’m a big person now.
“How would you go about planning to kill your mother and your own sister? How can you plan that?
“For you to plan to murder your mother and your sister, you must have really hated your sister and your mum. Cos you can’t plan that, I don’t care who you are, you cannot plan, especially your sister. You can’t plan that.”
“Me and Elizabeth would have…would have had, what, 30 years between…to live between us, cos we always said we were gonna grow old together.”
“And then Katie, she had all her life in front of her. I don’t think they should be let out at all.”
Murdered by my Daughter airs on Channel 5 at 9pm on Monday.