Reuters 2 minute read HONG KONG, July 30 (Reuters) - Hong Kong police said on Friday they were launching an investigation into booing of China's national anthem in a shopping mall broadcasting live the city's first Olympic gold medal win in 25 years earlier this week. More than 100 people gathered briefly on Monday night in a shopping mall to watch on a wide screen Cheung Ka Long claiming the Olympic men's individual fencing title. read more Police said they fielded complaints that some people booed during the award ceremony when China's national anthem was played, according to local media. Some shouted "We are Hong Kong," South China Morning Post reported on Friday.