A 14-year-old boy has been arrested on suspicion of murdering a teenager in Hertfordshire.
Jacob Abraham, 15, was stabbed in a service road behind his home in Hurst Drive, Waltham Cross, on Thursday evening.
Hertfordshire Police said he tried to run back home but never made it. He was found by his 19-year-old brother Isaac.
The arrested teenager, from London, has been released while inquiries continue.
Jacob had left the house in "good spirits" at about 20:30 GMT after receiving a series of phone calls, police said.
His brother became concerned when he did not return and searched the estate, finding him at 21:30 just 200 yards from his home.
Jacob, a keen boxer, lived with Issac, his mother, a younger sister and another brother, aged 26, police said.
They added that Jacob appeared to have met up with four to eight people soon after leaving the house and a number of young people were seen leaving the area on foot.
Police said robberies by youths on other youths had increased in Waltham Cross in recent months and this was one aspect of their investigation.
Det Ch Insp Jerome Kent, from the Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit, said: "Jacob left his home just before 8.30pm on Thursday and within an hour he was dead.
"Jacob was just 15 years old and his life has been tragically cut short.
"We know that other young people who knew Jacob will have information about his death and I'm appealing for those people to speak to officers.
"I would encourage parents whose children may have connections to Jacob to speak to them about providing information to police."
Police said Jacob died 10 days before his 16th birthday.