A 16-year-old boy was arrested in connection with the fatal stabbing of a young Afghan refugee in Twickenham, authorities have said. The suspect was in custody at a south-west London police station as of Thursday. The Met said that the murder of Hazrat Wali, 18, was still under investigation, and a motive has not yet been established. The Evening Standard reported that Wali was attacked on a footbridge on Tuesday, and collapsed on a busy sports field near Richmond upon Thames College, a school the teenager attended.

Wali, who came to the United Kingdom alone two years ago “to pursue a better life,” according to friends, was assailed by a group of boys. VICE News reported that the aftermath of the stabbing was witnessed by a number of rugby-playing schoolchildren, aged 12 and 13, leaving several of them in tears. A teacher on the scene attempted to give Wali CPR, but the Afghan teenager was declared dead at a hospital an hour later. Wali is the 26th teenager to be killed in London this year.