The boy – who has not been named – was found unconscious at what police are calling “a public location in Trinity”.
He was found by a member of the public early this morning and was taken to hospital, where he died.
Police have arrested three young men – two 16-year-olds and one 15-year-old.
A police statement announcing the death said that the four young men were all believed to have known each other.
The family of the dead teenager – who lived in St Lawrence – have been informed about his death.
The police have asked anyone with any information that might help in their investigation to call 612612.