Moise Djuku, is wanted in connection with the murder of Corey Dobbe on Sunday, June 13, this year.
Mr Dobbe was found injured on Harleston Close, Hull, at around 7.30pm and died a short time later from a fatal stab wound.
A team of 170 police officers are currently working on the investigation into the murder of Mr Dobbe.
A Crimestoppers reward of £5,000 for information leading to the capture of Moise Djuku has been issued.
Investigators have been following a number of lines of enquiries, however none have so far led to his arrest.
Detective Chief Inspector Alan Curtis, of Humberside Police, said: "Throughout the course of the investigation detectives have been working tirelessly around the clock following up on lines of enquiry provided to us.
"There has been a huge police operation surrounding this investigation and I’d like to thank members of the public for their continued support throughout the investigation.
"I would ask again for anyone who knows where Moise Djuku is to come forward and give us that vital information.
Anyone with information about Moise Djuku’s whereabouts can contact Crimestoppers anonymously by calling 0800 555 111.