He was among more than 450 veterinary professionals and students that signed an open letter urging the agriculture department to suspend the policy.

Wildlife officials used to go to extreme lengths, such as abseiling down cliffs and diving into drainage tunnels to rescue trapped pigs, Mr Tse recalled.

During previous sterilisation operations, wildlife officials had respected his judgement and never put down a pig unless it was necessary, said Mr Tse, who once operated on a boar that broke its snout and dislocated its jaw at the scene to save its life.

Mr Tse believed the government was probably under pressure to deliver quick results after high-profile cases of injuries, including that of the police officer and another involving a pop star’s mother.

But over time, sterilisation could have achieved the same goals, Mr Tse argues.

“Collars were also placed on pigs to track their movements, and the collection of these valuable data about their distribution and activities will come to a halt,” the vet added.

“The policy of killing the boars is unnecessary,” said Roni Wong of the Wild Boar Concern Group. She had attempted to intervene and lead the pigs back uphill at the first operation, only to be detained by police officers.

Mr Wong criticised the government for taking a barbaric approach instead of tackling the root of the issue, people who feed the animals illegally and draw them to urban neighborhoods.

“By re-introducing the policy, the department has lost all its credibility and the public trust,” Mr Wong stressed.

On Mount Parker, an employee at a biodiversity education centre admitted the wild pigs could be a nuisance as they gnaw at plant roots, but shooing them away requires only a simple act of communication.

“You stand behind them and clap, and they would leave, knowing they are not welcome,” she said. “Otherwise, they are free to roam anywhere. This entire hill is their home.”