A teenager, who died after being stabbed in Pimlico, central London, has been named as Hani Abou El-Kheir.
Officers were called to Lupus Street at 6.50pm on Sunday, where they found a 16-year-old who had been stabbed. Witnesses heard him screaming for his life.
The victim was taken to a south London hospital but died from his injuries at 8.45pm.
Family friend Mahmoud Abosiad said: "He was a lovely boy. He did not deserve to end up on a slab."
Mohammed Alzubaidi, 49, from nearby Peabody Close, said his friend had witnessed a gang made up of black and white teenagers carrying out the attack.
"He said they were carrying knives, some of them with wide swords. He said the victim was screaming and trying to get away."
Mr Alzubaidi's friend told him the gang had scattered and run off in different directions.
The teenager was a former student at Pimlico Academy, a short distance from the scene of the fatal attack.
In a statement, the school's principal, Jerry Collins, said pupils and staff "were deeply saddened to hear about the death of our former student Hani Abou El Kheir and extend our deepest sympathies to his family".
Mr Collins added: "Having left the Academy in 2009 Hani rejoined in December 2011 and was a pupil here until the summer of 2012. Hani was a popular boy who conducted himself in an exemplary manner and will be much missed."
The victim's mother Pauline Hickey, who lives 100 yards from the scene, did not want to comment. But an unidentified man said at the family home: "She's broken-hearted."
The scene of the attack is close to Pimlico Underground station and is bordered by many council estates.
A 58-year-old local resident, who did not want to be named, said there had been two murders in nearby Gloucester Street in recent years and a stabbing of a boy outside a row of shops in Lupus Street before Christmas.
"The violence that has started to occur around here is something else, it is frightening for all the residents. You used to be able to walk around at night but I am starting to be very wary, especially at night-time," she said.
No arrests have been made so far. Police have launched a murder investigation.
A spokesman for the Metropolitan Police said: "We must retain an open mind re the circumstances of the incident and any motive at this early stage."