A teenage Afghan refugee was stabbed to death on a sports field in south-west London in front of schoolchildren playing rugby. The victim, named as 18-year-old Hazrat Wali, from Notting Hill, was attacked at about 4.45pm on Tuesday on Craneford Way, Twickenham, yards away from Richmond upon Thames College, which he attended. Despite the efforts of a teacher who provided CPR after he collapsed, Wali was pronounced dead in hospital shortly after. A murder investigation has been launched. Munira Wilson, Twickenham’s MP, said police, who were yet to make any arrests, were “pursuing a key suspect who is still at large”. A relative of Wali’s, from Stanmore, told the Evening Standard that Wali came to the UK alone two years ago to pursue a better life, leaving his family behind in Afghanistan. His friend Sahil Kochay said: “He was a very good person. Very caring and loved everyone. He didn’t hold any hate towards anybody. He used to stand up for everyone. I wish I knew why someone would hurt him. He wasn’t the kind of guy to fight.” Year 8 pupils from nearby Richmond upon Thames school, aged 12 and 13, who had been playing rugby at the time, were said to be in tears as they looked on. Their teacher initially attempted to shield them, before trying to save the 18-year-old. A witness told the Evening Standard: “There was a teacher in a rugby kit, he was trying to save the boy. He was giving CPR. There were two girls next to him, they were crying. He was a real hero, it was a terrible scene. Five minutes before the incident a group of very noisy kids came along heading to the field. The next thing we knew, all hell let loose.” The attack reportedly began on a footbridge, where the victim and suspects had been arguing. A parent said a group of boys “scarpered” after they were approached by the teacher, before her 13-year-old son saw Wali collapse. A crime scene is now in place, with two tents erected on the field. Dr Jason Jones, the college principal of Richmond upon Thames College, said: “Our thoughts and prayers are with the student’s family and friends at this difficult time. This loss is sure to raise many emotions, concerns, and questions for our students, parents, staff and local community.” DCI Vicky Tunstall said: “We are still working to establish the motive behind this tragic attack and are following a number of leads. Officers have recovered CCTV from the area and spoken to a number of witnesses who described seeing a fight in the moments before Hazrat was attacked. We know a lot of people were on the field at the time and I’d urge anyone who has not yet spoken to police to contact us immediately.” Wilson offered her “deepest condolences” to Wali’s family after the “tragic and shocking incident”. The Lib Dem MP said: “The police are pursuing a key suspect who is still at large and forensic searches are ongoing at the site of the crime. The field and access to the railway bridge via Twickenham Rough remain closed off and will be sealed for at least the next 48 hours. “The police have significantly stepped up patrols in the area and will continue to do so for the next few days. I have urged them to continue doing so beyond this week. The college’s security team are also patrolling the area more intensively. “I will be reiterating my calls to the mayor of London and the Home Office to boost local police numbers.”