A killer who bludgeoned an elderly Hong Kong couple to death in their Canadian home five months ago, may have struck again, the couple's son said yesterday. The murder of a Chinese pensioner, Ku Shuk-kam, 62, two weeks ago, has shed more light on the killing of the retired primary school teacher Choi Chuk-tung, 75, and his wife, Choi Leung Chun-ho, 74, their son said yesterday. William Tsui Sai-leung, 48, said the murder in the same Vancouver suburb of Coquitlam bore many 'terrible similarities' to his parents' murders, including the age of the victim, the scene of the killing and general circumstances. Mr Tsui, head of a Chinese University laboratory, said he would contact the Royal Canadian Mounted Police (RCMP) for information. Like the Chois, Ms Ku was found dead in the basement of her home. There were no signs of a forced entry or struggle and the murder was committed on a quiet weekend when the rest of her family were out. Sources in Vancouver said police had tried to link the two murders, but nothing had been revealed to the public. Mr Tsui believes Ms Ku's murder proves his parents' killer conned his way into another Chinese victim's home. 'To me, both murders seem to be committed by the same person or persons,' he said. 'The murderer could pose as a salesman to get access and that would explain why there were no signs of any break-in. 'I strongly believe my parents' murders were not done by people known to my family. Both cases have many similarities.' In a letter to Mr Tsui, RCMP Constable Dave Strachan of the Serious Crime Section admitted police had run out of leads. 'This case is classified as a murder. We cannot say with 100 per cent certainty whether the motive for their demise was a result of a 'home invasion' or that it was a premeditated assassination,' he wrote. The elderly Chinese community in the area is stunned by the murders. A source said: 'Chinese senior citizens tend not to open doors wide to strangers. When they do open their door they leave only a gap.' The Chois were killed the day before their planned return trip to Hong Kong, their first since emigrating five years ago. Since the murders, the Chinese-Canadian community has begun some self-defence and anti-theft courses for 40,000 Chinese immigrants over 65, half of whom live alone.