Police arrested a 34-year-old man on suspicion of placing rat poison in cat food at Shek Kip Mei Park. No felines have been injured.
This video shows a volunteer from the animal abuse watch group attempting to confront the suspect in running gear.
The cat food placed in Shek Kip Mei Park could be seen turning black, allegedly mixed with rat poison.
Police received a report from a woman over the case at around 3 am. A pack of suspected rat poison and a 14cm long fruit knife were later seized on the 34-year-old man. He was later arrested on suspicion of cruelty to animals and possession of offensive weapons.
The animal welfare group says since mid-August, unknown liquid was found in the cat food used to feed stray felines in the park.
They then set up surveillance cameras nearby which helped uncovered the case.