Thieves may have stolen a moped shortly after its teenage rider crashed and suffered fatal head injuries.
Jamie Flanagan, 18, was critically injured when a moped overturned in Milverton Road, Willesden Green, north west London.
He was taken to the Royal Free Hospital after the crash, which took place in the early hours of Monday morning, but died two days later.
Officers today appealed for information about the moped and two crash helmets which were left at the scene when he was taken to hospital.
Detective Inspector Andy Rose, of the Alperton traffic unit, said it is not known if Mr Flanagan was the driver or pillion passenger.
He said: "Someone may have taken these items from the scene for a legitimate reason or for their own gain.
"It is important they are returned to us as soon as possible to assist the investigation into Jamie Flanagan's death.
"If you are in possession of - or know the whereabouts of - the items please contact police.
"You can be assured that we will speak to you in the strictest of confidence, however you may have come about this information."
The moped was a black Piaggio Typhoon 125, with red and blue striped stickers and Martini Racing logos. The registration number was P775 KOR.
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