A butcher died while trying to slaughter a pig in Hong Kong, the city’s police said, CNN reported.

The 61-year-old butcher, who worked in the Sheung Shui Slaughterhouse on the city’s northern outskirts close to its border with mainland China, was knocked to the ground by the struggling pig and sustained a wound from a 40 centimeter (15 inch) meat cleaver, police said.

The butcher had been about to kill the pig—which he had already shot with an electric stun gun—when it regained consciousness and knocked him over.

A colleague found the man unconscious with the cleaver in his hand and a wound on his left foot.

He was taken to hospital and was later certified dead.

The police force said the cause of death has yet to be determined.

The city’s Labour Department said it has launched an investigation.