Masked robbers broke into the luxury home of Shanghai billionaire Chau Ching-ngai early yesterday and made off with cash and valuables from a safe. The gang of four forced their way into the two-storey house - thought to be worth more than $100 million - in Perkins Road, Jardine's Lookout, through a ground-floor kitchen window using screwdrivers before tying up two helpers who were asleep nearby at 4am. They then burst into the unoccupied room of Mr Chau's 15-year-old son and broke into the safe without setting off the alarm. The gang left the way they got in. The son and his mother were asleep elsewhere in the house as the robbers struck. Mrs Chau later called police. It is believed Mr Chau was out of Hong Kong. No one was hurt in the incident, but two men and a woman were helping police with their inquiries. The gang evaded closed-circuit TV cameras and scaled barbed-wire topped walls to enter the grounds. Mr Chau, 39, known as 'Shanghai's Li Ka-shing', is considered the city's richest man. He plans to expand his property business into Hong Kong and bought the Jardine's Lookout property last year. He moved into the house with his wife and son less than two months ago.