Four dogs died excruciating deaths after coming into contact with poisoned bait on the roadside in Mui Wo on Lantau Island last week, the police and the pets' owners said. And a Filipino domestic helper, 42, fell ill after cleaning up the vomit of one of the dogs, her employer, Thomas Walther, said. Three of the dogs ate scraps of meat lying near Lick Hang Kindergarten in Tai Tei Tong village on January 6. They were taken to Mui Wo and Wan Chai clinics run by the Society for the Prevention of Cruelty to Animals, where they died, the SPCA and owners said. Police are investigating whether a dog poisoner is behind the deaths. They received five reports of nine dogs falling prey to suspected poisoning in Mui Wo between January 7 and 13. The Filipino woman was taken to Mui Wo General Outpatient Clinic after she vomited and was suffering from dizziness, severe headache and a sore neck, said Walther, 42, a pilot. She began to recover within 24 hours. The dogs suffered several hours of painful convulsions before they died. "Bebe stood up and started to scream - I've never heard her scream like that before," he said. "I guess that's when the pain started. She just ran and screamed and ran and screamed to try and run off the pain, banging into walls." Bebe died early on January 7. Walther's neighbours said their dog Kiddo died in a similar way. The SPCA said it was awaiting the results of toxicology tests, but one veterinarian said it may have been poisoning by strychnine, an ingredient common in rat bait that can also be fatal to humans. An Agriculture, Fisheries and Conservation Department spokeswoman said it would conduct an autopsy on one of the dogs. She said the use of strychnine as a pesticide was illegal. A bounty of HK$30,000 has been offered for information that will lead to a prosecution. Anyone who deliberately harms a dog could be fined a maximum of HK$200,000 and jailed for up to three years.