Five years after the unsolved murder of Joseph Burke-Monerville, a friend of his grieving family has insisted: “Someone knows who these people are.”

Gus John will take his appeal to the streets when he speaks at a memorial service to mark the anniversary tomorrow (Fri).

Joseph, a Nigerian prince, was just 19 when he was shot in the head at point blank range as he sat in a car with his twin brother Jonathan and elder brother David in Hindrey Road, Lower Clapton, on February 16, 2013.

Police believe it was a case of mistaken identity.

Three men were due to stand trial for his murder in 2015. But they were acquitted when defence lawyers argued the case was bound to fail because it relied on the evidence of just one gang member.

Last year Joseph’s family filed a complaint with the Independent Police Complaints Commission, now the Independent Office for Police Conduct, into how the investigation was handled.

Speaking on behalf of Joseph’s father John, Professor Gus John told the Gazette: “You can’t bear the pain of something like that, but that pain is relieved if you know the perpetrators are brought to justice, and they aren’t likely to visit that pain on any other family.

“The failure of police to bring Joseph’s killers to justice is a major scandal, but you can’t blame the police alone, because there are people within our community who know who these people are.”

Grenadian-born Prof John, who was awarded the Martin Luther King Memorial Prize in 1972 for the contribution of his book, Because They’re Black, to racial harmony in Britain, said Joseph’s death cannot be seen in isolation.

“One of the requests that I have is that the Black Lives Matter movement doesn’t appear to have this phenomenon on their agenda,” he said.

“If black lives matter, they matter – irrespective of who’s taking those lives. Given the energy they put into defending young people who are killed by the police or neo-Nazis, one would like to see Black Lives Matter engaged with communities pretty much on a full-time basis, building a mass movement, so that communities are taking effective action to route out that murderous scourge from our midst.”

He added: “I was working in Hackney as a director of education in 1992 when the first set of killings associated with youth violence started seriously.

“Between then and now there have been hundreds of young people killed, and there is a major issue to do with killing within the Caribbean community.”

Joseph and Jonathan had been sent to secondary school in Nigeria by their parents who were concerned about the “violent culture” amongst younger people in London.

In September 2012 they returned to start university degrees in forensic sciences – but just five months later Joseph was tragically killed.

“As you can imagine it was utterly devastating for the entire family, none less than Jonathan,” said Prof John.

“I supported the family through that whole process, until the Trident team arrested who they thought were the perpetrators, but they had to let them go.

“It was extremely traumatic, and no family recovers from that kind of thing as you can imagine.

“The tragedy is that since Joseph was killed there have been any number of killings year on year in London, and so what is one’s family’s grief multiplies to the extent where it becomes a community health issue.”

A memorial service will take place tomorrow at 6.30pm at St John at Hackney Church in Lower Clapton Road, before mourners walk to the site of the shooting to pray at 8pm.