Police officers were called to the Town Street area in Horsforth just before 3pm on Tuesday to reports of an assault, West Yorkshire Police said. The boy was rushed to hospital in a critical condition, but did not survive.
A candlelit vigil was held on Tuesday night not far from the police cordon, with around 50 young people in attendance. People could be seen hugging each other, with some wiping away tears, as they stood around a bench covered in floral tributes.
Two bunches of white flowers had also been left at a cordon on Church Lane, as forensics teams were pictured at the scene.
One tribute on social media read: “You were a kind and caring young boy with so much to give.
“I don’t know if you realised how many friends you had and how many people care about you but they were out in force for you tonight laying flowers and lighting candles for you at your bench. Sleep tight little one.”
A male teenager has been arrested in connection with the incident, and the victim’s family have been informed, police said.
“Our investigation is at an early stage and we are carrying out extensive inquiries to establish exactly what led to this needless loss of a young man’s life,” said Detective Chief Inspector Stacey Atkinson.
“We understand the immense impact and huge shock a tragic incident of this nature will will have on the community locally. Our neighbourhood police team are working with partners, including schools in the area to offer support and reassurance.
“We have already spoken to a number of witnesses and are keen to hear from anyone who has information about the incident.”
Paul Bell, the headteacher at nearby Horsforth School, said the boy who was stabbed is a former pupil.
In a message to parents, he said: “You will be aware of a distressing incident in the community today, involving a former student of Horsforth School who was stabbed on St Margaret’s Avenue. The police are aware and working with the school.”
Dr Bell said: “We are aware of the distress and upset this has caused students and staff who know the student. We will be supporting students and staff in school and will update you as soon as we are able. We have limited information at this time.”
Leeds City Council’s deputy leader Jonathan Pryor said he was “heartbroken” by the news, adding: “I know the distress and upset this will cause students and staff. While there isn’t much we can say at this stage, an arrest has been made, and we will be supporting Horsforth School in every way we can.”
A parent at the school, who did not wish to be named, said: “It’s horrible. It’s shocking because it’s a nice area. You read about these things happening in London and you think it’s dangerous to be a teenager there, but you don’t think it would happen here.
“I just keep thinking about the parents. He probably went out this morning and they were expecting him to come home, and he’s not there.”
Witnesses are urged to contact West Yorkshire Police by calling 101 or online, quoting reference 0952 of 7/11. Alternatively, call independent charity Crimestoppers anonymously on 0800 555 111.