This is the latest update in the case of Deshaun Tuitt, who was fatally stabbed in Highbury Fields shortly before 9pm on 4 August 2022.
Since his death, detectives have shared numerous images online of people they want to speak to, with seven teenagers charged with murder.
Although almost two years have passed since the murder, no conviction has yet been handed down.
Detective Inspector Ben Dalloway said: “Our investigation into Deshaun’s death is ongoing and we are keen to hear from anyone who can name the man in the photo.
“I urge anyone with information about the man pictured or Deshaun’s murder to do the right thing and contact me in person or anonymously.
“His family desperately needs answers and we are doing everything we can to get them the justice they need.
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“If the man in the picture is you, please do not wait for us to contact you, please contact us without delay.”
Anyone with information that could assist police should contact 02083 453 865, quoting 7948/04AUG22.
Those wishing to remain 100% anonymous can also call Crimestoppers on 0800 555 111.