Bangladesh detectives hit the jackpot when they stopped Mohammad Belal at Chittagong airport carrying some surprising excess baggage.
Under questioning, the 37-year-old admitted he had a dozen chunks of gold weighing 1.4 kilograms, or three pounds, stashed in his rectum.
Gold smuggling in Bangladesh is at a record high, officials say, with the country emerging as a major route into neighbouring India, which has slapped high taxes on gold imports.
Authorities have seized 1.1 tonnes of the precious metal at airports in the past three years -- an unprecedented haul.
Investigators believe it is the tip of a golden iceberg. They say it is bought by jewellers or smuggled into India, the world's biggest buyer of gold, and is also bankrolling a booming trade in drugs and illegal cattle.
As monitoring has been stepped up, barely a day passes without another seizure.
Detectives on Wednesday discovered 13 stone-sized gold tablets hidden in the wig of a 45-year-man as he passed through Dhaka's international airport.
Smugglers are increasingly resorting to more drastic methods to evade detection, officials say.
‘Hiding gold bars in electronic appliances, wheelchairs or in toys has become old tactics. Now they are increasingly using their rectum to carry gold,’ Moinul Khan, Bangladesh's customs intelligence chief, told AFP.
‘We give them a lungi (cloth worn by men around the waist) and a polythene bag, ask them to defecate and there comes gold from the anus. Some women were even found having carried gold in their vaginas.’
More than 100 people -- mostly Bangladeshi migrant workers -- have been arrested since 2014 for gold smuggling at the country's three international airports, police say.
Khan said smuggling networks often included air hostesses, airport ground staff and cleaners and corrupt security personnel.
‘They have a huge network involving a lot of people,’ he said.
- Gold mafia -
Despite heightened vigilance plenty of gold is finding its way onto the black market, Khan said.
An aide to Prime Minister Sheikh Hasina last year told the Bangladesh Jewellers Samitee (BJS), a lobby group representing local jewellery shops, that authorities could only expect to detect 10 percent of the gold smuggled through its porous borders.
Bangladesh -- a low-lying nation on the Bay of Bengal -- does not have any gold mines of its own and relies on imports to fashion rings and other treasures for its booming middle class.
The country has imposed strict quotas and huge customs duties on gold, effectively choking off legal bullion imports for flourishing jewellery outlets.
The BJS has repeatedly called on the government to allow the bulk import of bullion at reasonable rates.
Khan said a ‘sizeable amount’ of smuggled gold was sold to local jewellers.
Detectives and customs agents recently seized nearly half a tonne of gold from outlets of one of Bangladesh's biggest jewellers after the company failed to provide import documents.
The jewellers' association said it sources its gold from individuals pawning personal items, an explanation detectives reject.
‘We don't buy gold from the black market,’ the association's president Gangacharan Malakar told AFP.
‘The raids are conspiracies to destroy a vital industry which employs 2.2 million people.’
Malakar pointed the finger at India -- the world's largest buyer of gold -- saying most of the bullion smuggled into Bangladesh, mostly from the Gulf, was destined for the Indian market.
Huge taxes on gold imports into India have fuelled a smuggling industry at the leaky border, said Mustofa K. Mujeri, former chief economist of Bangladesh's central bank.
‘This is a dangerous, powerful and politically-backed gold mafia. They don't leave any evidence, and play with blood money,’ he said.
Khan said gold was financing other illicit trade near the border, including livestock smuggled illegally from India.
‘Bangladesh is an obvious transit point of many illicit transactions, such as drug trade, human trafficking and cattle smuggling,’ Mujeri said.