Two security guards were robbed of a cash box containing $2.5 million by two gunmen just after they left a branch of the Bank of China in the Lok Fu Centre, Wong Tai Sin, yesterday. The robbery happened at 11am when two guards from Brink's Hong Kong - one carrying the cash box and the other armed with a shotgun - were intercepted as they walked towards their van outside the shopping mall. One of the robbers used the handle of his gun to club the guard carrying the money box, while the other attacker took his colleague's shotgun and fled. The robbers were said to be between 40 and 50. Heavily armed policemen, assisted by tracker dogs, later combed the area but failed to find any trace of the robbers or the guard's shotgun. During the search, officers found the opened cash box abandoned near the mall but all the money, in $500 notes, was gone. A worker's glove, believed to have been dropped by one of the gunmen, was found nearby. A police source said the security company had used an old-fashioned cash box for the transfer. It did not have any electronic devices or dyes to protect the consignment. The 23-year-old guard who suffered head injuries was admitted to Queen Elizabeth Hospital for observation, while his colleague, 42, was unhurt.