It was April 2016 in Spalding, Lincolnshire, when a story broke that would eventually baffle the entire UK. Most people know them as the "Twilight Killers." But when you look at the raw facts of what Kim Edwards and Lucas Markham did, the cinematic nicknames feel almost too light. They were 14. Just kids, basically. Yet, they carried out a double murder so cold it left seasoned detectives struggling to find words.
The victims were Kim’s own family: her mother, Elizabeth Edwards, 49, and her 13-year-old sister, Katie.
Honestly, the timeline of this case is what really gets people. It wasn't just a heat-of-the-moment outburst. This was a "cold, calculated, and callous" plan, according to the courts. It took days of plotting. It involved signals, bathroom windows, and a backpack full of kitchen knives.
What really happened in that Spalding house
Kim Edwards and Lucas Markham weren't exactly hiding their intentions from each other. They were "besotted," as the Court of Appeal later put it. A toxic, isolated bubble. Kim felt a deep-seated grudge against her mother and sister. She thought Katie was the favorite. She resented them. And Lucas? He just went along with it. He shared her hatred.
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On that Monday night, Lucas walked about 30 minutes to Kim's house. He knocked on the window. Nothing. Kim had fallen asleep. He just went home and put the knives back.
He came back the next night.
This time, Kim was awake. She cleared the bathroom windowsill so he could climb in quietly. They stood in that house and had one last talk. "Are we doing this?" They agreed they were. Lucas took the lead. He went into Elizabeth’s room and stabbed her in the throat while she slept. Kim stayed in the bathroom, listening to the "gurgling" sounds.
Then he killed Katie.
The chilling "Twilight" aftermath
If the murders were horrific, the 36 hours that followed were arguably weirder. They didn't run. They didn't panic. They shared a bath. They had sex. They ate ice cream. And yeah, they watched four Twilight movies.
When the police eventually kicked the door in on April 14, they found the two of them lying on a mattress in the living room.
"Where is your mother?" the officer asked.
"Upstairs," Kim replied.
No tears. No shaking. Just a flat, matter-of-fact answer.
The legal battle and the naming ban
For a long time, the public didn't know their names. Under UK law, children under 18 usually get total anonymity. But the judge, Mr. Justice Haddon-Cave, felt this case was different. He argued that the public couldn't possibly understand the motive without knowing that the killer was the victim's own daughter.
Kim tried to claim "diminished responsibility." Her defense argued she had a mental abnormality that messed with her judgment. The jury didn't buy it. She was found guilty of murder. Lucas, on the other hand, pleaded guilty from the jump.
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They were both handed 20-year minimum sentences.
However, in 2017, the Court of Appeal knocked that down to 17 and a half years each. Why? Because the judges felt they should've gotten more credit for their early admissions to the police. Even though they are Britain's youngest double murderers, the law had to weigh their age and the specific sentencing guidelines for youths.
Where things stand today
It’s been nearly a decade since those events. As of 2026, Kim Edwards and Lucas Markham are young adults in their mid-20s. They are still serving those sentences. Because they were sentenced "at Her Majesty’s Pleasure" (now His Majesty's), they don't just get out when the clock hits 17.5 years. That’s just the minimum they have to serve before they can even ask for parole.
The Parole Board will have a massive job. They have to decide if people who could do something that "chilling" at 14 can ever be safely let back into society.
Key takeaways from the case:
- Folie à deux: Many psychologists pointed to this as a "shared madness." Alone, they might have been troubled kids. Together, they became a lethal unit.
- The Power of Grievance: Kim’s resentment over perceived favoritism was the primary engine. It shows how unchecked childhood grudges can spiral in extreme environments.
- Legal Precedent: This case fundamentally challenged how the UK balances a child's right to anonymity against the public's right to know about "exceptional" crimes.
If you are looking into the history of youth crime in the UK, the Spalding case remains a primary case study for forensic psychologists. You might want to look into the "Mary Bell" case or the "James Bulger" trial for context on how the British legal system handles children who commit the unthinkable. Both cases share similar debates over whether rehabilitation is truly possible after such an early, violent break from social norms.
Your next step for research:
Check the official Sentencing Council guidelines for "Sentencing Children and Young People" to understand how judges calculate these minimum terms. It explains why their 20-year sentence was legally contentious enough to be reduced on appeal.