On the evening of April 13, 2016, and her boyfriend carried out a despicable double murder before settling in for a cosy movie night.

The couple, who were just 14 years old at the time of the killings, ruthlessly killed Edwards' mum, Elizabeth, 49, and younger sister Katie, 13, in the culmination of a wicked plan the so-called had concocted together at a McDonald's.

Jurors at heard how, on the night of the murders, Markham had walked for about 30 minutes along Coronation Channel in Spalding, Lincolnshire, with four knives packed into his rucksack. He then knocked three times on a bedroom window, in a signal they had pre-arranged together.

Opening a bathroom window, Edwards allowed Markham to enter the property from the shed roof, advising him on how to move around her family home quietly and undetected.

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As would be later detailed during their trial, Edwards and Markham were involved in a twisted, intense relationship, which Edwards' mother, Elizabeth, disapproved of. Dinner lady Elizabeth attempted to split the young couple up, even contacting their school in an attempt to stop them spending so much time together.

This left Edwards and Markham furious, and a sinister plan began to emerge, which psychologist Emma Kenny later compared to "Romeo and Juliet, but in a very dark manner", in an interview with the .

Things began to escalate in March 2016, when Edwards was hospitalised following a suicide attempt. After she was discharged, she and Markham ran away together and were eventually found five days later, living in a tent in a neighbouring town.

On April 9, 2016, Edwards and Markham barricaded themselves in Markham's room before heading to Edwards' home to retrieve her contraceptive pill. Once they arrived, they discovered Elizabeth had cleared Edwards' belongings out of the house, even given some of her possessions to Katie, whom Edwards already harboured resentment towards.

In one police interview, Markham revealed the first time he raised the idea of killing Elizabeth and Katie. He remembered: "I said 'I wish I could kill them' and she said 'yeah', she thought I was joking but I was joking and then she realised I was being serious so she started being serious as well."

The pair planned for Markham to stab Elizabeth in the throat to stop her screaming, while Edwards murdered Katie. Markham later told officers: "I went into her mum's room, stabbed her in the neck while she as asleep, then smothered her face with a pillow."

Markham stabbed Elizabeth eight times, twice in the neck, once in the shoulder. The stab marks on her hands showed that the mother had struggled against her assailant. Recalling how she'd heard noises coming from her mother's room during the viscous attack, Edwards told police: "I went into the room to see what was going on because I heard noises and I wanted to check.

"He was on top of her with like a pillow over her head. I though I heard her say 'get off me' but I'm not entirely sure. The after about 10 minutes of Lucas putting his weight on her, she was dead."

Edwards ultimately decided she couldn't kill Katie, as she "couldn't take away those hopes and dreams". It's was then that Markham took over, slaughtering little Katie in the bedroom she'd shared with Kim. He remembered: He said: "I went into Katie's room, which was the same room as Kim's. I thought I stabbed her but it was the mattress and then I smothered her face with a pillow too."

After the bloody killings, the pair took a bath, ate teacakes and ice-cream, and had sex, before cuddling up on the sofa to watch the teenage vampire movie, Twilight. They had intended their plan to end with their own suicides, but they ultimately decided not to go along with it, instead spending the next two days watching films, having sex and eating ice-cream. All the while, the bodies of Elizabeth and Katie lay upstairs.

Eventually, their absences started to be noted, and officers broke into the property. Police found the teenage couple downstairs, and could barely bring themselves to believe they were the ones responsible for the horrific scenes they encountered upstairs.

Delving into some of the simmering tensions at the heart of her troubled family life, Edwards described her Katie, as "an angel" and herself as a "train wreck", claiming that she'd felt her mother had loved her little sister more.

She felt her mum loved her little sister - but she herself felt outside the family unit. Following her arrest, Edwards told officers: "Ever since I was young, I have never got on with my mum, I knew she favoured my sister more than me. Even when she said she didn't, she was lying."

Both Markham and Edwards were given life sentences and ordered to spend at least 17 years behind bars.

If you're struggling and need to talk, the Samaritans operate a free helpline open 24/7 on 116 123. Alternatively, you can email or visit their site to find your local branch

Do you have a story to share? Email me at julia.banim@reachplc.com

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