A 15-year-old boy has been arrested on suspicion of murder after a teenager was stabbed in Leeds.
West Yorkshire Police found the 16-year-old boy with a stab wound after being called to reports of an assault in Harehills Lane at around 3.45pm on Friday.
The boy was taken to hospital for treatment, but died shortly afterwards.
Detective Superintendent Pat Twiggs appealed for witnesses who may have filmed the attack on their mobile phones.
He said: "This tragic incident happened in a busy area at a busy time of day with large numbers of people going about their daily business.
"I am appealing directly to anyone who witnessed the incident or has information that could help our inquiries to come forward.
"It is also possible that people may have recorded footage on their mobile phones and I would again encourage those people to come forward."
The 15-year-old suspect was held in custody while a forensic team scoured the scene for evidence.
Anyone with information should call police on 101 or Crimestoppers anonymously on 0800 555 111.