Lucas Markham stabbed his girlfriend’s mum and sister in the neck. He will serve a minimum of 20 years in prison

The court was told Lucas, who admitted murder, used a kitchen knife to stab his girlfriend’s mum and her sister in the neck after attacking them as they slept at home in Spalding, Lincolnshire, in April last year.
Kim, who helped to plan what was described as: “cold, calculated and callous” act by the prosecution, denied murder, claiming to be suffering a mental abnormality which impaired her ability to form rational judgments.
Jurors heard she was the “driver” behind a “cold and brutal” plot to kill her own mum and sister.
The defendants showed no emotion as they were sentenced to life – but family members wept.
The pair were ordered to serve a minimum term of 20 years behind bars each, but that has now been reduced to 17-and-a-half years on appeal.
the pair, who butchered Elizabeth and Katie before having sex, eating ice cream and watching Twilight, made a suicide pact  they did not carry out.
The killers,  14 at the time, also agreed to plead guilty.
But she denied murder and admitted manslaughter due to diminished responsibility.
Our source said: “The boy wanted them  to admit the killings, and he wanted to revel in the notoriety of the  murders.
“That, and their failed suicide pact, drove a wedge between them.
“They did not talk or look at each other during the trial  and they have not written or tried to speak while they have been locked up.
“The girl is really upset about the split but the boy wants nothing to do with her.”
The pair were  convicted last month of murdering Elizabeth and Katie at a house in Spalding, Lincs.
Nottingham crown court heard  they had a grudge against Elizabeth and planned the killings for days.

Tragic ! Katie was killed by her sister who had ‘brutality and contempt oozing from every pore’. Katie [left] was stabbed in the neck by Lucas Markham as she slept, all ochestrated by her sister, Kim [right]

It took a jury of seven men and five women two hours and 30 minutes to find her guilty of both charges by unanimous verdict.
In his closing speech prosecutor Peter Joyce QC said “brutality and contempt oozes from every pore of this girl” and she held the lives of her alleged  victims as cheaply as she would “a hamster or a goldfish”.
He told the jury: “You know from her police interview just how determined those two children were to take two lives. You know just how callous they were, just how cold they were.

Victims: Elizabeth Edwards with daughter Katie who were both found dead in their home in Spalding

“You know how they planned it and you know in awful detail how they carried it out.
“But you also know this girl was the driver between those two.
“She told the police: ‘We made sure that we were definitely OK with it and he continuously asked me if I still wanted to go through with it and I said yes’.”
Kim Edwards then 14 told police “I’d felt like murdering for quite a while” after she and her boyfriend killed a mum and daughter, a court heard.
The teen said she and her boyfriend Lucas Markham, also 14, had “a grudge” against her mom, dinner lady Elizabeth Edwards, 29, and her 13-year-old sister, Katie.
The teen Twilight fan also said the plot to kill half her family  started as “a joke” that “escalated”, a court heard.
Kim now 15, told police in an interview: “He was joking. Then he realized I wasn’t joking. Then Markham said he wasn’t joking either and it escalated from there.”
Kim Edwards and Lucas Markham both 15, are accused of hatching the plot to kill church-going Elizabeth Edwards, 49, and youngest daughter Katie from a McDonalds three days before the attack.
Kim told police in an interview: “He constantly asked me if I wanted to go through with it and I was, like, yes and I asked him and he said yes.
“We decided on the Sunday, but I had felt like murdering for quite a while.”
Describing the killings, the girl said: “He gave me his backpack. I opened it slowly because I didn’t want to make too much noise.
“I took out a black t-shirt with four knives in it. There were two large knives with black handles, like average kitchen knives.
“He said are you sure you want to do this? I said yes, but then in the end I couldn’t do it so he did it.”
Elizabeth Edwards told the boy to “get off” her and was heard “struggling and gurgling”, jurors heard today.
Nottingham Crown Court heard how her 13-year-old daughter Katie died moments later after the boy crept into their rooms and repeatedly stabbed them in the throat as they slept.
It is alleged the 15-year-old then suffocated his victims with their own pillows while his female accomplice listened to them “struggling and gurgling” at around midnight on April 13.
The pair were then said to have taken a bath together and eaten ice cream and tea cakes.

The teen couple celebrated the killings by having sex and watching Twilight

Dubbed the Twilight killers, they are the youngest ever couple to be convicted of double murder in the UK.
The court heard for how Markham said in police interviews that his victim Liz Edwards had “scratched his face, back and bum” as he stabbed her to death.
He also told officers she stopped struggling and went limp after about three minutes.
Following the verdicts Mr Justice Haddon-Cave thanked the jury for doing “their public duty” and told the court: “This has been a difficult and important case. I would like to pay tribute to the police and those who have investigated this matter.
“It’s an exceptional case by any standards.
“I would like to pay tribute to the quiet dignity shown by those in the public gallery.”
The court has since heard Edwards remains on a five-minute suicide watch in custody.
The court was also told the Markham has been telling fellow inmates about his sickening crimes at a youth offenders facility.
Mr Joyce added: “Just imagine that scene by the riverbank, the boy asking his girlfriend: ‘Do you want to go through with it? Do you really want to do this? Are you sure?’
“It would never ever of happened if she had said no. He was offering not to do it. She could have stopped him.
“She couldn’t bring herself to do it so she got him to. He showed her how she should do it, how she should hold the knife.Peter Edwards, the father of victim Katie Edwards, arrives at court
“[She showed] Sheer brutality and utter contempt for her victims. It oozes from every pore of that girl in that interview.Peter Edwards, the father of victim Katie Edwards, arrives at court
“Afterwards she said she felt ‘a bit sad’. A bit sad – as if it was a goldfish or a hamster.”

Dinner lady Liz was killed by teens described as “a time bomb waiting to go off”

Dr Indranit Chakrabarti had previously told the court the girl’s adjustment disorder prevented her from forming a “rational judgment” and having the ability to plan.
Giving evidence, the child psychiatrist said: “She was thinking under the influence of a recognised medical condition.
“She was unable to make any rational judgment and could not plan, these are symptoms of the adjustment disorder.”