Mr Urquhart, 55, was killed in front of his girlfriend as they left their local pub in Marylebone High Street.
A black Yamaha motorcycle the gunman used for his getaway was found yesterday in a street near by and was being examined by the police. It was bought in November. No attempt was made to change the number plates and police believe it was bought specifically as a getaway vehicle, leading them to speculate that a contract for Mr Urquhart's murder was put out and agreed in October.
Police examined the victim's car, which was equipped with three telephones and a fax machine, and which he used as an office for many of his business deals.
Mr Urquhart told some people he was a former hod carrier who built up his fortune during the property boom of the 1970s and 1980s.
Police are looking into Mr Urquhart's business, including his interests in Cayman Islands and Jersey tax havens. According to his brother, Lovat, a north London vending-machine dealer, he had not been so active in business in the past three years. Lovat Urquhart told police that his dead brother had been nervous about possible street attacks.
The murdered man returned from southern Spain on 30 December after spending two weeks visiting his 84-year- old mother and playing golf.
Fears were growing last night for a millionaire businessman who vanished from his home.
Detectives found a pool of blood in the garage where David Martin's BMW car should have been parked, and stepped up their hunt after he failed to keep important business appointments.
Mr Martin, 49, has not been seen since 30 December, when he left his home at Naphill, near High Wycombe, Buckinghamshire, without money or clothing.
He moved to Britain from Australia 20 years ago and built up a business manufacturing loudspeakers.
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