A 51-year-old woman was grabbed and pulled out of her car after stopping for bogus police officers, who then stole her vehicle.
The victim was driving along Elmbridge Road, Hainault, on February 6 when an old style silver BMW 5 Series car activated sirens and a flashing blue light.
Believing it was a police car, she pulled over to the side of the road, but she was then grabbed by a man who opened her door.
He seized her arm and pulled her out of the car before getting into it and driving off towards New North Road.
The victim, from Hainault, was unhurt after her ordeal and declined an ambulance.
The stolen car, a grey, Ford Mondeo Zetec, had belonged to her son and was later found in Verderers Road, Hainault.
The suspect is described as a black man, aged 23 or 24, 6ft tall and slim, with short black shaved hair. He is also thought to have a distinctive buck tooth.
A police spokesman said residents should only stop for a car with police lights if they are 100 per cent certain it is the police.
They should park in a public place, keep their doors locked until they are sure and ask to see a warrant card through a closed window.
If you have any information about the incident, call 101.
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