The booming pet delivery service in South Korea has been hit by controversy after an online report claimed that two cats had died while sealed inside a box.

A picture of a polystyrene box in which the cats allegedly died surfaced online along with a detailed story of the animals’ death.

The account, posted on a Facebook page of an animal welfare group, said the seller had punctured air holes in the box but that the cats died in transit.

Demand for pet deliveries have flourished, with the report of the cats’ death only one of many incidents of animals suffering or dying before they reach their new owners.

Earlier this month, South Korea passed a new law to regulate pet delivery businesses and to ensure the animals are treated humanely.

The law sets guidelines that animal sellers either must see the buyers in person to hand over animals to them or use animal delivery services that meet standards, such as a minimum size for animal enclosures and access to enough air and water, reports the Wall Street Journal.