Thai police said they had discovered six underfed tigers in specially-built cages on the roof of an apartment building on Monday, arresting a man who claimed he had been planning to open a zoo.
Four adult cats and two cubs were found at the property on an industrial estate in Pathumthani province, north of Bangkok, in the raid by police from Thailand's Natural Resources and Environmental Crime Suppression Division.
A 28-year-old man, who lives in the building, was arrested at the scene and claimed to own the animals.
"The man said that he was preparing to open a zoo in the province", said police Captain Montri Neepasee, who said the animals had not been given enough food and did not look "completely healthy".
The tigers were fed with around 10,000 baht's worth ($322) of chicken bones a month.
"They did not get enough nutrients for their growth," Montri said, adding that the cubs were "stressed" in the small cages.
He said the owner of the building, a cousin of the arrested man, denied all knowledge of the caged tigers.
Montri added that the other occupants of the flats had apparently ignored the presence of the big cats on the roof.
"The renters are mostly factory workers and they do not seem to care about environmental issues," he said.
Police said that the tigers will be sent to an animal sanctuary in a nearby province on Tuesday.
A second officer involved in the case, Colonel Panpong Panklump, said the arrested man had been charged with illegal possession of wildlife, which carries a maximum penalty of four years in prison.
He added he believed the tigers would have been sent to Vietnam, where there is demand for "their meat and skins".
Thailand, a hub of international smuggling, is one of just 13 countries hosting fragile tiger populations. Worldwide, numbers are estimated to have fallen to only 3,200 tigers from approximately 100,000 a century ago.
In February police busted a grisly exotic wildlife slaughterhouse in Bangkok when officers caught four men in the act of chopping up a tiger in a residential home.