A prisoner is being questioned over the murder of a man who died 13 years after he was shot in the heart.
Marvin Couson was attacked at the Lime in London bar in Shoreditch in May 2002. He was left unable to communicate or leave his bed, and died in 2015.
The Met said it was questioning a 37-year-old man who has links to a Birmingham gang, which detectives believe may be involved in the attack.
A £40,000 reward remains on offer to anyone with information.
Det Ch Insp Noel McHugh said: “At this stage everything points to a dispute between organised criminal gangs from London and Birmingham.
“It is all the more sad as Marvin was not involved in gangs or criminality and we believe he was an entirely innocent victim of a dispute that had nothing to do with him.”
‘Suffered until death’
Mr Couson, then 26, fled when shots were fired inside the bar on Curtain Road on 12 May 2002.
While outside, his friend was struck by a T-reg red or burgundy Ford Fiesta, thought to contain at least two black men.
He grappled with the front seat passenger then as he walked back towards the bar, a gun was fired and he saw Mr Couson lying on the ground.
It is unclear if the shot came from the car, but police are still trying to trace its occupants. A man was arrested 11 days later, but released with no further action.
Mr Couson was taken to hospital with serious injuries to his heart and other organs. He died on 8 August 2015 and a post-mortem examination gave the cause as brain injury suffered as a direct result of the shooting.
His sister, Margaret Couson, said: “As time goes by people say the pain of losing a loved one will become less and you will find a way to cope. This is far from true.
“There is not a single day that goes by where Marvin is not in our thoughts.
“He did not just suffer a gunshot wound to his heart, he suffered until his death – all of 13 years, two months and 27 days in a hospital bed with hypoxic brain injury.
“What makes the pain remain with our family is the mere fact that there are individuals who know a lot more than they are willing to disclose.”