Teenager Guilty of Stabbing Footballer Charlie Cosser at Sussex Party

Seventeen-year-old Charlie Cosser, a promising young footballer from West Sussex with dreams of becoming a groundsman at Chelsea Football Club, was stabbed three times in the chest at an end-of-term party in a field in Warnham, Horsham on July 23, 2023. He died two days later, leaving behind a family shattered by loss — and a community forced to confront the brutal reality of youth knife violence. The attacker, 16-year-old Yura Varybrus, was found guilty of murder on June 4, 2024, after a three-week trial at Brighton Crown Court. He was sentenced to life in prison with a minimum term of 16 years. But for Charlie’s father, Martin Cosser, the verdict felt hollow. "Nothing can bring my little boy home," he told the Liphook Herald in October 2025. "There are so many people who I feel have escaped justice."

The Night It All Changed

The party in Warnham was meant to be a celebration — the last night of term for students from local schools. Charlie, described by friends as kind-hearted and quiet, had no history of violence. But when a girl at the gathering told him she felt uncomfortable around Yura Varybrus, Charlie did what many adults would hesitate to do: he asked Varybrus to leave. What followed was a sudden, violent escalation. Witnesses said the two boys exchanged words, then fists. And then, in a moment that would haunt a town for years, Varybrus pulled a knife. Charlie was stabbed three times in the chest. Emergency services arrived within minutes, but the wounds were fatal. He died in hospital on July 25, 2023. The knife? Never recovered. The motive? Not revenge, not robbery — just a teenager’s unchecked anger, and the lethal ease with which a young life can be erased.

A Father’s Promise, Shared With Millions

In the days after Charlie’s death, Martin Cosser didn’t retreat. He turned to TikTok. What started as raw, tearful videos of him holding his son’s football jersey soon went viral. One post, where he whispered, "I promised you justice," was shared over 12 million times. Another showed him kneeling at Charlie’s grave, saying, "I’ll spend the rest of my life making sure no other parent feels this." His posts didn’t just grieve — they educated. He spoke about the weight of carrying a knife, the split-second decisions that lead to irreversible consequences, the silence that follows when a child doesn’t come home. Schools across Sussex began showing his clips in assemblies. Teachers reported students asking questions they’d never voiced before. By 2025, Martin had co-founded Charlie’s Promise, a charity dedicated to "educating, inspiring and supporting young people" to reject violence. The organization now runs workshops in 17 schools, partners with local police, and trains peer mentors. "We don’t preach," Martin told ITV News. "We listen. And then we show them what loss looks like."

The Trial and the Silence

The trial at Brighton Crown Court lasted 21 days. Prosecutors played security footage of the party, phone recordings of Varybrus boasting about the stabbing afterward, and medical reports detailing the fatal wounds. The defense argued Varybrus acted in self-defense — a claim the jury rejected after just four hours of deliberation. Throughout the proceedings, Yura Varybrus sat expressionless. He didn’t look at Charlie’s family. He didn’t cry. When the guilty verdict was read, Martin Cosser collapsed into his wife’s arms. Their daughter screamed. Their son, silent, stared at the floor. Varybrus, now 17, showed no reaction. "He didn’t even blink," said ITV reporter James Dunham, who covered the trial. "That’s what sticks with you. Not the crime. The absence of remorse."

The Documentary That Shook a Nation

On October 21, 2025, ITVX aired the first episode of Season 2 of TikTok: Murder Gone Viral — The Killing of Charlie Cosser. It was the most-watched true-crime documentary on the platform that week. The episode didn’t just recount the facts — it showed Martin Cosser watching his own videos for the first time since Charlie’s death. "I’ve seen this a hundred times," he said, voice cracking. "But today… today I heard his laugh in the background of one clip. I didn’t even remember he’d recorded it." The documentary, flagged for strong language and distressing scenes, also revealed that Varybrus had posted about the stabbing on social media within hours — a post later deleted but recovered by police. It showed how quickly violence spreads online — and how easily grief can be weaponized into activism.

What’s Still Unresolved

Martin Cosser doesn’t believe justice is done. He points to two other teenagers who were at the party that night — one allegedly held Charlie down while Varybrus stabbed him, another filmed the attack. Neither has been charged. The Crown Prosecution Service says evidence is insufficient, but Martin’s lawyers are pushing for a fresh review. "The system let us down," he says. "They punished one boy. But what about the ones who stood by? What about the culture that made this possible?" Charlie’s Promise has since launched a campaign called "Who Was Watching?" urging witnesses to come forward. A hotline has received over 300 tips. None have led to charges — yet.

Why This Matters

Charlie Cosser’s death wasn’t an isolated tragedy. In 2023, 28 teenagers under 18 were killed by knives in England and Wales. In 2024, that number rose to 34. West Sussex recorded 12 knife-related assaults involving minors in the year after Charlie’s death — a 47% increase from the previous year. Experts say social media plays a dual role: it fuels bravado among teens who post videos of weapons, but it also gives families like the Cosser’s a platform to fight back. "We’re seeing a new kind of advocacy," says Dr. Elena Ruiz, a youth violence researcher at the University of Sussex. "Parents aren’t waiting for politicians. They’re using algorithms to save lives."

What’s Next

Martin Cosser is now lobbying for mandatory knife crime education in all UK secondary schools. He’s met with the Home Secretary and is working with the Department for Education on a pilot program. He also plans to release a book next spring — not about grief, but about choice. "Charlie didn’t die because he was in the wrong place," Martin says. "He died because someone chose to bring a knife to a fight. And we have to teach kids that choice has consequences." The first anniversary of Charlie’s Promise’s national rollout is set for September 2026. By then, Martin hopes to have reached 500,000 young people. He’s not waiting for another tragedy to act.

Background: A Life Cut Short

Charlie Cosser was born in Horsham. He played midfield for the local youth team, West Sussex Colts. His favorite player was N’Golo Kanté — not for the goals, but for the work ethic. "He never took a day off," Charlie once told his coach. "Even when he was tired, he still ran." His dream wasn’t to be a pro. He wanted to work the pitch at Stamford Bridge. To mow the grass. To keep the lines crisp. To be part of something bigger than himself. His school kept his boots. They’re still in the locker room. No one’s touched them.