Police believe that Mikolaj Majer, who is missing from Watford, may be in the west London area.
Officers are still appealing for the public’s help to trace him.
Mikolaj, aged 15, was last seen in Watford on Monday, November 25.
He is described as white, 5ft 3ins tall, of slim build, with blue eyes and short black hair.
Mikolaj could be wearing a diamond earring and a tracksuit.
If you have seen Mikolaj since he was reported missing or have information about where he has been, please call Hertfordshire Constabulary’s non-emergency number 101.
If you believe you are with Mikolaj now or have seen him in the last few moments, please call 999 immediately.