A Scotland Yard spokesman said the early indications were that the attack took place at a nearby residential address and that the victim and attacker were known to one another.It is thought Mr Martinez managed to leave the scene before collapsing in the street.Witnesses said he was barefoot as he ran screaming from the building.Police also said the attack was not believed to be gang related.One witness told the Evening Standard: “My husband told me the boy had been running and then collapsed right in front of our house. I called the police and we started bringing towels and blankets for him. “The police arrived in like three minutes and they started cutting his clothes. We saw he had been stabbed once on both his legs, twice in his chest and once near his back. He was also bleeding from his head.” Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Paramedics battled for 40 minutes to save David Martinez’s life David Martinez was the 21st murder in London this year A 26-year-old man who was stabbed to death in east London has been named by police as Spanish national, David Martinez.Mr Martinez was fatally knifed on Wednesday afternoon at a property in Leyton in east London.His was the 21st homicide in London this year.Police said they were initially called to reports of a stabbing in North Birkbeck Road at 4.26pm.When officers arrived they discovered Mr Martinez suffering from knife injuries.Paramedics battled for 40 minutes in an attempt to save his life, but he was declared dead at the scene at 5.10pm. “His skin was white, like powder white. At one point he tried to get up. We asked him what language he spoke and he said Spanish. He didn’t talk after that. He was just shaking, turning white and blue.