Five Class IX students were detained in Baruipur on Tuesday for allegedly murdering 17-year-old Prosenjit Biswas following a dispute over a football match in which his team had won.

One of them stabbed the Class X student in the neck, while the others watched.

“The boys are in custody. The investigation is still on,” said Kankar Prasad Barui, inspector-general of police, Presidency Range.

Police said the five were produced before the Juvenile Justice Board in South 24-Parganas for a preliminary assessment, following which the board will decide whether the case should be transferred to a Children’s Court.

The post-mortem report suggested that the victim was repeatedly stabbed and died of haemorrhagic shock caused by heavy blood loss.

Biswas had gone to a spot about 500m from his home around 7.30pm on Monday after calls from a friend. A group of teenagers was waiting for him, the police said.

The confrontation centred on the football match.

The police were still trying to ascertain whether on-field rivalry was the sole trigger.

One of the accused allegedly pulled out a knife and repeatedly stabbed Biswas.

“I had called Biswas to the spot. I tried to save him and ended up injuring my right hand,” said the friend.

“The attackers arranged to take both of us to Baruipur hospital,” the boy said. Biswas died at the hospital.

Three of the accused allegedly hid under a cot inside a police outpost at the hospital before being detained.

A mob attacked the police outpost after learning that officers had rescued them. Protesters also blocked the road leading to the hospital. Later, senior police officers pacified the situation.

Biswas’s father is a rickshaw puller, and his mother works as a hospital attendant.

“We want justice for my brother. The accused should not be released immediately,” his elder sister said.