Tributes have continued to pour in for Michael Adegbite, a fitness instructor and football coach who was attacked after he advertised his secondhand MacBook on Gumtree for £200.
He and a friend went to meet someone they believed was a buyer in Enfield on Sunday evening — but were confronted by three youths.
Detectives believe the men lured the 28-year-old to the rendezvous with the intention of mugging him for the laptop.
Mr Adegbite and his friend managed to snatch the laptop back and the suspects ran off.
Police say that a short time later, a second friend joined the victim and the three men set out to look for the group who had attempted to rob them. Minutes later there was a confrontation and a scuffle in the street and Mr Adegbite was stabbed once in the chest. He died at the roadside 30 minutes later despite frantic attempts by neighbours and paramedics to save his life.
Today his heartbroken family said they had been “destroyed” by his death. They said Mr Adegbite had been a role model to young people during his time as a coach of youth football team Eastside United FC in Hackney and as a teaching assistant at Heathcote School, Chingford.
His brother, speaking on behalf of his family, said: “He wanted to help young people from troubled backgrounds, show them the right path.
“He talked to them about the dangers of knife crime and in the end he was the victim of it. It’s just senseless. He was killed over a laptop. No life is worth that little.”
Mr Adegbite worked at Leyton Leisure Centre and lived in Chingford with his mother, a nurse, his father and younger brother.
A family friend told the Standard: “It’s just heartless. Michael never made trouble, he was one of the most peaceful men you could meet.
“He was just selling the laptop for a few hundred pounds online. It’s something people do every day and he was killed for it.” Queens Park Rangers striker Jay Emmanuel-Thomas paid tribute to his friend online, saying: “The way life works ain’t fair, but you’re in a better place so guide us and protect us to happiness and success.
“When will the youth of today change, taking people’s lives is not cool.”
Mobo-winning rapper Jahmaal Fyffe, better known by his stage name Chip, tweeted: “Another good brother just stabbed and dead. Praying for change. Condolences to your family.”
Scotland Yard has appealed for witnesses to the assault in Lackmore Road, Enfield, at about 6.55pm.
Three men have been arrested on suspicion of murder and are being questioned by homicide detectives.
A police spokesman said the victim and his friend had driven to a pre-arranged meeting point in near-by Auckland Close.
He said: “He was met by three men who attempted to rob him of the laptop computer. The victim and his friend were able to snatch back the laptop before getting back into their car. The suspects made off on foot.
“A short time later, a second friend joined the victim, and the three men sought to find the group who had attempted to rob them.
“They found the people they believed to be the robbers in Lackmore Road, Enfield, at around 6.55pm and an altercation took place in which the 28-year-old victim was fatally stabbed.”