A teenager who was stabbed to death in northwest London is believed to have first had a car driven at him and then been chased by four people before the fatal attack, police have said.
Sixteen-year-old Drekwon Patterson was found with stab injuries and given emergency treatment at a roadside before being taken to hospital on Thursday evening, but he died the following morning.
Scotland Yard have now released images of a car and a van they want to trace in relation to their investigation.

A black Ford Mondeo using registration number YR54 NHN was seen driving from the scene in Preston Road, Brent, shortly after 11.30pm on Thursday.
It was later discovered burnt out.
Investigators believe it was the car used to drive towards Drekwon, who was from the Wembley area.
Police are also keen to trace the driver of a van seen on CCTV stopping briefly near the scene, and are appealing for them to come forward as a witness.
Source: Sky News