Ali Nasrollahi, 22, was stabbed while he was with his girlfriend.
He was stabbed after an argument over £120 debt.
Ali Nasrollahi, known as Ali Nasro among his friends was stabbed in the chest in Woodside park in North west London.
His girlfriend called 999 to the suburban avenue where his friends were trying to save his life.
One witness said Ali came with his girlfriend in their car before having an argument with another man over £120 debt.
The onlooker said: ‘They were saying, “You were supposed to give me my £120, why didn’t you bring my £120?” Then three men turned up in a car and they all got into an argument.
‘One of them then slashed him across the chest. I ran out with tea towels and tried to save him by putting pressure on his chest wound.
‘By this time his girlfriend had got out of the car when she saw him staggering away, and was just screaming and screaming, “They have stabbed him”.
‘While he was on the floor, she was screaming, “Ali, I love you, I love you, Ali”. She was praying there on the floor next to him and reciting the Koran while he was in and out of consciousness.’
Metropolitan police are looking for four men in connection with the murder.
Detective Inspector Julie Willats, from the Met’s Homicide and Major Crime Command, said: ‘We know that the victim had driven to Woodside Grange Road with one of his friends and met up with another friend, who had also driven there.
‘At some stage, the victim interacted with a group of up to four suspects, during that interaction we believe he was stabbed.
‘The group of suspects then ran off down Grangeway and into an alleyway that leads onto Woodside Avenue.
‘I would like ask for the public’s help. If you were near Grange Way or Woodside Avenue yesterday afternoon and saw anything that might help us then please get in contact.
‘I am directly appealing to anyone who may have seen up to four suspects running away from the alleyway that runs from Grange Way. Did you see a group and see which way they went?’
A friend of Mr Ali, Mohammed Musalam said: ‘He is a nice guy. I have known him since we were young. His dad passed away from cancer just three months ago.
‘He was so upset since his dad died. He wasn’t the same since then. He was the coolest guy. He would never get in trouble, not in fights.
‘He was all about his girls, that was it. I am in shock.
‘He wasn’t the fighting person he was all about work, money and girls. He was one of the local boys. We used to play together after school. He was into football and music. He used to DJ.’
Mr Ali was taken to a hospital around 4:45pm but died after a short time.
Today, a police cordon lines the blood-spattered road and the garages behind the terraced houses.
One neighbour said: ‘I was in the kitchen talking to my friends while my garden door was open. My dog started barking – it was an unusual barking, and I went to see what was happening. I heard a woman screaming and I heard shouting and screaming.
‘It wasn’t normal. I went round and saw he was on the floor and had been stabbed. A boy started to give him mouth-to-mouth and a lady who lives next to the scene tried to keep the pressure on the wound.
‘She was pushing where he had been stabbed to keep the bleeding under control. His girlfriend was crying and shouting over the phone for the ambulance to come.
‘I said, “How can I help?” And the people said to get towels. I rushed and gave them to them and that’s when the police and ambulance arrived.
‘It’s a nice area and I have never seen these things happen here before. I didn’t sleep at all last night. I was just thinking, “How is this possible?”’
A woman who have been living in the area for over 20 years said: ‘I saw the aftermath and I’m still in shock. It has affected everybody’s lives but most of all it has destroyed the victim’s life. I was having a late lunch and there was a ring at the doorbell.
‘I saw all the police and the flashing lights and a police officer asked if I saw anything. I saw a man lying on the floor while two orange-clothed medics worked on him.
‘We have had problems in the area with the private garages behind our homes. We think they are smoking and exchanging undesirable substances.’
Another neighbour said: ‘I had my window open and I heard them talking about owing Ali £120 and why didn’t the guy pay the money. They said it was stealing.
‘I went into the house and went upstairs to put my shopping away and looked out of my window and they were still arguing. The older man handed Ali or his friend some money.
‘They took the money then Ali, the one who got stabbed, was talking to four of the black guys. He got them really upset then they started beating him. They were punching him up against the tree.
‘The older guy who took out the money then took out a knife and cut him. He slashed him with his right hand. Ali held his chest and struggled backwards. I ran downstairs. I tried to save his life.’
Police have not arrested anyone yet and have appealed to the public if anyone have any information to please come forward.
Detectives were today searching in bushes for evidence. One man who knew him visited the scene and said: ‘He was a normal, nice guy. He was too young to die like that. I can’t believe it.’