Dog owners were warned last night to surrender their pets immediately if they savage someone. On Tuesday, a mixed-breed dog that mauled a domestic helper was taken away for observation after two futile attempts to contact the owner. The mongrel that allegedly attacked domestic helper Lilibeth Tumaca late last month in her employers' flat in Causeway Bay was taken away by government dog catchers, about two weeks after the incident. The dog, named 'Lucky', remained under observation at the Agriculture, Fisheries and Conservation Department's animal management centre, and investigations were continuing, a spokeswoman said. She said in all cases of dog bites, owners had a responsibility to surrender their animals for observation. 'If the dog bite is mild, the dog can remain at home, but should not be allowed to go out for seven days.' But in serious biting incidents, the animal had to be taken to the department's animal management centre, she said. 'We need to observe it for symptoms or abnormal condition. All dogs brought to the AMC after dog bites will be tested to see if they have rabies.' She said Hong Kong had remained rabies-free since 1987 because all pet dogs had to be microchipped, licensed and vaccinated. Lo Wing-lok, an expert in infectious diseases, said the department should offer preventive treatment in all serious dog-biting cases. Dogs from the mainland, which has an epidemic of rabies, may find their way into Hong Kong, Dr Lo said. In September 2001, Lorna Capayan, 37, died of rabies. She had been treated for viral encephalitis and the diagnosis of rabies came only after her death.