Detectives investigating the murder of Marvin Couson - who died 13 years after he was shot in Shoreditch - believe he might have been an innocent victim in a dispute between rival criminal gangs from London and Birmingham.

Last week officers interviewed a 37-year-old serving prisoner under caution, who has links to a Birmingham gang.

And Detective Chief Inspector Noel McHugh, who is leading the investigation urged a person who has previously called the Crimestoppers charity anonymously to call in again.

“I would like to speak to you personally as soon as possible as you may have further information that could be vital to our enquiries,” he said.

Marvin died two years ago, having been confined to a hospital bed unable to communicate or do anything for himself since he was shot in 2002 outside the Lime in London Bar in Curtain Road – which is now the Queen of Hoxton.

A £40,000 reward remains on offer to anyone who can provide information leading to the arrest and prosecution of those responsible.

DCI McHugh added: “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. The smallest piece of information could really help.

“A lot of time has passed and loyalties change so I hope for the sake of Marvin’s family - and his two children who are now teenagers - that someone can find it within themselves to do the right thing.”

Margaret Couson said the loss of her brother has left the family with a feeling that “life is so cruel”. “Individuals like you and me in a split second become victims of crime and a life-time of suffering follows,” she said.

“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.

“Information sharing is all I ask from each and every one of you - there are individuals 15 years on from Marvin’s fatal shooting that have still not come forward with information. This is heartbreaking to know.”

Anyone with information is asked to call 020 8785 8099 or Crimestoppers anonymously on 0800 555 111.