Two 17-year-olds have been arrested in connection with the murder of Rizwan Darbar, police have said.
The teenager died after his friends were approached by a gang who demanded they hand over a mobile phone on Sunday afternoon.
Rizwan, 17, was stabbed as he listened to music with two friends in West Ham Park, east London. He died at Newham General Hospital shortly before 7pm.
Confusion remains over whether Rizwan intervened when his friend's mobile was taken.
His heartbroken family paid tribute to the "very, very loving" teenager.
Rizwan, who was fasting during Ramadan, had gone to the park earlier that afternoon with friends to get out of the house, his brother Tausif, 19, said.
"He was fasting and bored so he went out with some friends. They were walking through the park waiting for some other friends when some black boys came up to them," he said.
"I think Rizwan twitched or moved or something. An argument broke out.
"Rizwan and his friends were doing nothing other than listening to music on the phone. They were reasonable lads doing nothing whatsoever."
Mr Darbar said of Rizwan, an avid West Ham United fan: "He was dedicated to all of us, especially our mum. He was very, very loving and had lots of friends. He was always the good one, the quiet one."
