Police have now charged five teens with the murder of James Hunter in Sydenham.
Mr Hunter, 18, was stabbed in the chest during a fight between groups of youths in Wells Park Road, Sydenham, on May 31.
Although ambulance crews attended, Mr Hunter - who police say was not a gang member - was pronounced dead at around 9.25pm.
A Lewisham 15-year-old boy and a Sydenham youth, aged 17, have both been charged with murder and wounding with intent. They are due at Bromley Youth Court today (June 9).
Two 16-year-old boys, from Catford and South Norwood, will appear at Bromley Youth Court tomorrow (June 10), also charged with the murder.
A further boy, aged 17, is due to appear at the Old Bailey today, also accused of the killing.
Last week, police arrested two boys aged 13 and 15, who have been bailed pending further inquiries.
Anyone with information can call police on 020 8721 4868 or Crimestoppers on 0800 555 111.