Detectives investigating the fatal stabbing of a teenager in London today arrested a 16-year-old male, Scotland Yard said.
Frederick Moody, an 18-year-old student, was knifed in the stomach just yards from his front door in Lambeth, south London.
Vida Oblitey, a neighbour who described "Freddy" as like a son to her, said she had been with his mother when he died in hospital last night.
She said: "Freddy was a very handsome boy, a lovely boy - and whoever has done this has taken the only son away from a very happy family."
After visiting Frederick's mother and his sister Tamara, Ms Oblitey said the family were still "struggling to understand who would do this".
Frederick was found mortally injured in Guildford Road by police called to an assault just after 7pm yesterday.
He was pronounced dead in hospital at 8.15pm, making him the 21st teenager to meet a violent death in London this year.
The 16-year-old boy was arrested at his home in the Brixton area in the early hours of today.
The latest death came on the day official statistics found there were 350 knife crimes committed in England and Wales every day. The British Crime Survey (BCS) showed nearly 130,000 took place last year - and the total does not include offences involving under-16s.
At the latest murder scene, police were examining a green Peugeot 106 and had cordoned off streets. Residents were not being allowed back into their homes while a cordon around the area was in place.
Last night, one woman, who did not wish to be named, said she heard an argument break out and left her flat. She said she saw a body lying in the street, claiming it lay there for 45 minutes before police arrived.
Edward Skurfield, 19, who lives on Guildford Road, said: "I have lived here for three years and my friend has lived here for 11 years and we have not heard of any knife crime in that time in this area. It is so upsetting because people keep dying."
Keith Bayley, who lives directly opposite Frederick's home, told how he saw the teenager lying in pools of blood. He said: "One of our neighbours came and knocked on our door and told our son there was a body lying on the street.
"There were a lot of paramedics trying to revive him - he was there for about 20 minutes, I think. Then they took him away in an ambulance, but until then he was just lying there on the road, fighting for his life."
Mr Bayley said he now fears for the safety of his own 14-year-old boy.
He added: "Sometimes there is noise on the street round here - it is like anywhere in south London, but you don't expect this on your doorstep. It changes everything round here. My 14-year-old son has asked to be picked up from school tonight. It just changes everything."
As police combed the streets in south London for evidence today, across town, the funeral of another teenage stab victim, 16-year-old Ben Kinsella, was taking place. The aspiring actor's death in Islington, north London, prompted a spontaneous youth protest against youth violence in the capital.