Police are continuing their murder investigation after footage emerged showing several people attacking the 16-year-old victim in Wembley.
Drekwon Patterson, from Wembley, was driven at and chased by four people before being stabbed to death in Preston Road on February 18.
Police are currently trying to remove video footage from social media platforms "to prevent further distress to the family".
In the eight-minute footage, seen by this paper, the teenager is seen being chased and attacked by four people.
The group can then be seen running into a black Ford Mondeo - leaving Drekwon for dead.
A Met spokesperson said: "We are aware of CCTV footage relating to the murder being circulated on social media.
"This has not been released by the Metropolitan Police. Enquiries show this was uploaded by a member of the public.
"We are seeking to have the material removed from social media platforms to prevent further distress to the family.
"The MIT (Murder Investigation Team) are aware of the CCTV existence and continue with their investigation."
A black Ford Mondeo with the registration number YR54 NHN was seen driving from the scene in Preston Road shortly after 11.30pm on February 18.
It was found, burnt out, in Silver Jubilee Park on February 19.
Det Ch Insp Richard Leonard said: “I believe this car was used in an initial attempt to injure Drekwon in a collision on Preston Road.
"After the Mondeo had been driven at him, Drekwon ran away and was chased by four suspects who had got out of the car, before being caught and fatally stabbed."
In a previous appeal, officers were seeking the driver of a white van which can be seen in the video idling at the side of the road before driving off.
Det Ch Insp Leonard said: “I also want to trace the driver of a van, which was seen on CCTV to stop briefly near to the scene, who might have witnessed a crucial part of the incident.
"I am appealing for that driver to please come forward as a witness.”
Anyone with any information can call the incident room on 020 8721 4622 or call police on 101 quoting CAD 8167/18Feb.
Alternatively, contact Crimestoppers anonymously on 0800 555 111.
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