A man tried to steal a minibus after the owner left it with the engine running in a Brighton street.
He was thwarted by the owner who heard the door being opened.
The owner got in to the Volkswagen Transporter before the thief had managed to drive off and they struggled for control before it crashed into a parked car.
The thief jumped out and, although a passer-by tried to restrain the thief, he was helped by three friends before they escaped in a car.
Sussex Police said that the incident happened just after 3pm on Monday (3 January).
The thief tried to take the minibus in Ditchling Rise, Brighton, although he managed to drive for only about 100 yards, swerving as he struggled with the owner.
He hit a parked Rover car after a black estate car blocked his path.
When a passer-by stepped in, three men got out of a black Renault Megane and threatened him.
They all got into the Renault, including the thief, and headed south along Winchester Street.
The man who tried to steal the minibus is described as white, aged 18, with a very pale complexion, gaunt, of slim build, with yellow-tinged skin under the eyes and dark spiked hair. He was wearing an old-fashioned anorak.
One of the men stayed in the car. He is described as white, in his early twenties, with short possibly brown hair, a big face and red chubby cheeks.
One of the other suspects is described as a white man with a Liverpudlian accent, in his mid twenties and with short dark hair. He was wearing a padded jacket.
The black Renault Megane RS is described as having modified bodywork, possibly lowered with an additional rear spoiler.
The VW minibus owner was unhurt.
The Rover and the minibus received minor damage.
The minibus is being forensically examined for evidence and house-to-house inquiries are being completed.
Anyone with information is asked to contact Sussex Police on 0845 6070999 or the independent charity Crimestoppers anonymously on 0800 555111.
