A POOL of blood lies under a street sign near a smashed pair of glasses in the gutter and a running shoe. A policeman picks up a ring and slips it carefully into a plastic bag as others gather the belongings of the dead and injured of a tragic night's thrill-seeking on Kowloon's roads. Just a few hundred metres away from the grisly scene on Salisbury Road, Chief Staff Inspector Steven Wordsworth shakes with rage. From a secret vantage point, the officer in charge of a covert anti-road racing operation was preparing for his team of 40 men to swoop on the drivers. But suddenly, there was a bang, the wrenching of metal and screams. A four-tonne truck had ploughed into a row of young people who had gathered to watch their weekend entertainment. For 30 minutes, the crowd had stood cheering as racers roared along Canton Road in front of the row of plush tourist hotels and swerved into Salisbury Road. The police had not yet decided they had enough evidence - and a lot is needed to prove that a motorist is not simply out for a fast drive - to move in and nab the racers when the truck slewed across the road and into the spectators, killing two and scattering the rest. Mr Wordsworth swore. ''Look at this,'' he said, continuing to curse under his breath and hurrying with some others towards the door. The group stopped. They were high up in a building several hundred metres from where a seething crowd had swooped on the victims and the overturned truck. ''We had better call in the uniformed guys,'' was the advice, presumably inferring that they were on the ground and could get there quicker. There was also the unspoken understanding that road race enthusiasts have no love for the unit's plain-clothes officers. There were police on the scene within two minutes. ''We'll wait. We'll keep the operation going,'' said Mr Wordsworth. Someone explained that after past swoops, the racers had been back on the roads as soon as the coast was clear again. By 4 am, a smaller crowd had gathered at the same junction, and the surveillance team noted the return of a couple of cars which had been on the circuit before the accident. But they soon slipped away - either home or to another venue. With the morning light approaching at 6 am, the message went out from the team's command post on Canton Road that it was time for them to go home too. One officer had his own explanation for why there would be no more racing that night: ''It would be bad fung shui after what's happened here.'' As Mr Wordsworth left his position, he said: ''Two dead was not the result we wanted, we were after some arrests. But maybe what has happened tonight may have switched some people off the idea of racing.''