[Image: Shaquan Sammy-Plummer]
Detectives investigating the murder of 17-year-old Shaquan Sammy-Plummer are now offering a £20,000 reward for information.
The substantial amount is on offer for information that leads to the arrest and prosecution of those responsible for Shaquan's death.
Officers will be returning to the scene today, Tuesday 11 August, from noon to hand out appeal leaflets and speak to local residents and passers-by.
Police were called at around 21:35hrs on Friday, 30 January to reports of a young man collapsed on the pavement at Berkeley Gardens, Enfield N21.
Officers and London Ambulance Service attended and found Shaquan, who lived in Islington, suffering from a stab wound.
He was taken to the Royal London Hospital in a critical condition where he died a short while later.
A post-mortem examination at Fulham Mortuary gave cause of death as a single stab wound to the chest.
Investigating officer Detective Chief Inspector Jamie Piscopo, from the Homicide and Major Crime Command, said: "It is believed Shaquan was with two friends when he became involved in some kind of altercation that resulted in him being stabbed in the chest.
"His friends tried to help him along with local residents but his injuries were too severe.
"We still don't know what the altercation was about and we hope the offer of £20,000 may encourage someone with information, no matter how small, to come forward.
"Were you in Berkeley Gardens that night? Did you see or hear anything suspicious? Have you heard talk since about what happened to Shaquan? Please contact us."
Nine people have been arrested in connection with the investigation so far. Four have been released with no further action and five - [C] a 17-year-old girl from N21; [E] a 17-year-old boy from N9; [G] a 19-year-old man from N21; [H] a 29-year-old woman from N9 and [I] a 17-year-old boy from N9 - remain on bail until the end of September pending further enquiries.
[C], [E] and [G] were arrested on suspicion of murder, [I] on suspicion of murder and perverting the course of justice and [H] was arrested on suspicion of assisting an offender.
Shaquan's mother Jessica Plummer said: "I would be very grateful if the people that witnessed my son's murder could come forward to provide the police with information to bring those responsible to justice."
Anyone with information is asked to call the incident room on 020 8345 3715 or Crimestoppers anonymously on 0800 555 111.