The police have urged a 16-year-old murder suspect to hand himself in and warned members of the public not to approach him.
George David is a suspect in the killing of Gabriel Petrov Stoyanov, who was stabbed on 4 November in southeast London.
The public have been warned to immediately call 999 if they see him.
The teenager may be being protected by others, said Detective Chief Inspector Kelly Allen.
“George, my message directly to you is that you must attend a police station immediately,” said the officer.
“We believe it’s possible George is being hidden or moved around by people he knows.
“My message to those people is that if you are working to frustrate our inquiries you should be very much aware of the trouble you could find yourself in.
“We will seek to arrest and prosecute you to the fullest extent of the law,” warned DCI Kelly.
The suspect has links to Bromley and Orpington, the Metropolitan Police added.
A boy aged 17 and another aged 14 have already been arrested this week on suspicion of murder and remain in custody.
Mr Stoyanov, 21, was stabbed on Bromley Road in Downham just before midnight last Friday. He was taken to hospital by ambulance but died the next afternoon.
Anyone who sees George David is urged to call 999, reference CAD 8645/4 Nov. Information can also be given to 101 or tweeted @MetCC using the same reference.