A group of men assemble outside a 12th century temple on a hot April day in Puri, India, preparing to venture deep inside to a pitch-black vault where piles of gold and silver jewellery are stored under lock and key.

To enter Jagannath Temple, dedicated to an important Hindu deity, the group of 16 archaeologists, Hindu priests and government officials have to pass through metal detectors. Their skimpy loincloths are required as a security measure along with oxygen masks in case the vault, unopened for more than three decades, lacks breathable air.

Their instructions are simple: check the structural integrity of the vault and ignore the millions of dollars’ worth of antiquities stashed inside.

Anyone who spends much time in India’s Hindu temples is accustomed to being just steps from extreme wealth. Locked away in hundreds of the country’s largest temples is a staggering amount of gold, weighing as much as 8.8 million pounds, the World Gold Council has estimates. Under current market rates, that stockpile would be worth roughly $160bn (£121bn).

But despite their abundance of ancient riches, India’s temples are often poorly managed. With security measures lacking, they can be a tantalising target for thieves.

The April expedition does not take long. An hour after entering the temple, the men emerge, telling a crowd of waiting pilgrims that they had not needed to enter the locked vault, known as the Ratna Bhandar, because they had been able to peer inside through the bars of a gate.

But two months later, another explanation was leaked to local news outlets: the men had not been able to go in because the keys to the vault were missing.

The response is swift. A top temple administrator is fired. Officials with the state government of Odisha, which includes Puri, call for an investigation. Soon after, they discover that eight pounds of gold donated by visitors was also missing from the temple’s administrative offices.

The Jagannath Temple forms part of the Char Dham pilgrimage (Reuters)

Around Odisha, suspicion quickly mounts that some of the antique jewellery in the vault had been pilfered by what a local journalist, Sandeep Sahu, calls “a criminal nexus of temple officials and servitors” who had access to the keys.

The theft of riches from temples is common in India. In one of the largest such cases, a New York art dealer, Subhash Kapoor, is implicated in the theft of $100m worth of rare antiquities from remote, unguarded temples across India.

Operation Hidden Idol, as the investigation involving Kapoor is called, found that some of the items, such as a 1,000-year-old bronze statue of the elephant-headed Ganesha, ended up at the world’s leading museums, including the Metropolitan Museum of Art. Kapoor is facing trial in India.

But the hive-shaped Jagannath Temple in Puri, which forms part of the pilgrimage known as Char Dham – a four-part circuit travelled by Hindus to attain salvation – is far from an easy target.

A tight-lipped committee controls who can enter, where donations of money or jewellery are stored and how that information is disseminated to the public. The strict entry rules are designed to safeguard both the temple’s status as a sacred space and the treasures it contains.

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In 1984, Indira Gandhi, then prime minister, was famously denied entry because her husband was a follower of Zoroastrianism, an ancient monotheistic religion. Even today, priests guard the entrance, turning away non-Hindus and some non-Indians from sects such as Hare Krishna, which is popular in the West.

An internal temple report from 1978 explained the policy – unusual for temples in India – with an analogy: “If the petals of a beautiful rose are torn and dissected for the purpose of investigating the ingredients of its colour and smell, then the rose no longer remains a rose. It becomes rubbish to be thrown away.”

In the 1930s, Mahatma Gandhi, the leader of India’s independence movement, refused to enter the temple in protest against its entry restrictions, according to Ramachandra Guha, an Indian historian. The temple eventually opened its doors to some Hindus who had been barred previously, including Dalits, a lower caste. But the insular mindset remains.

This year, the temple made headlines when India’s Supreme Court suggested changing the rule preventing non-Hindus from entering. But many recommendations were abandoned.

“There’s a very long history of absolute reactionist bigotry,” Guha says of the temple’s exclusionary policies.

A 50kg, two feet high and one foot wide lock is used to guard the offerings made by devotees at the temple of Lord Jagannath (Reuters)

Reports of internal strife have also tarnished the temple’s reputation over past decades. Managers of the temple said in the 1978 report that “misappropriation, theft, lawlessness, harassment of pilgrims and exploitation had become the order of the day”.

That same year, to encourage transparency, an inventory was made of the vault. Temple officials reported finding a hoard of nearly 500 pounds of antique silver and gold ornamental jewellery designed to adorn statues of gods.

The vault last was opened in 1985, according to RN Mishra, a former temple administrator, who says he and a group of officials had retrieved some gold for maintenance work and promptly returned the key to the district treasury.

After the furore this year over the loss of the key, temple caretakers say they found a duplicate in the record room of the local magistrate’s office. Instead of quelling anger, the apparent discovery inspired more questions: when was the duplicate key made? Was it real? And where was the original?

Mishra calls the loss of the original key a “gross negligence”, and says that a duplicate had not existed when he was administrator and that he was not aware of one ever having been made. “One key, one lock,” he says.

Dibyasingha Deb, a member of Puri’s royal family and chairman of the temple’s managing committee, says accusations of mismanagement are unfair. He shifts blame to outsiders trying to “make us a laughing stock”.

“When people write about these incidents, and they don’t have any faith in our religion, our culture, they would like to make it a very sarcastic sort of a way of projecting things,” he says.

The inside of the temple remains off limits for many (Alamy)

But Pitambar Acharya, a lawyer in the Orissa High Court, the highest one in Odisha state, says he felt that temple caretakers were bluffing on what he calls the “key loss hullabaloo”.

Last month, Acharya and other officials from the Bharatiya Janata Party, an opposition party in Odisha, lodged a complaint with the police against top state officials in charge of tracking temple valuables, citing their failure to inventory jewellery in the vault regularly and questioning whether a duplicate key even existed.

“There has been a clear breach of trust,” he says, relating to unanswered questions on the loss of the temple key and the supposed discovery of a duplicate.

Outside the temple, in a packed plaza where men hammer together wooden chariots to be used for a festival, anger is palpable among priests, shop owners and visitors.

“The government is hiding facts,” says Satyavaan Sahu, 31, a worker at a nearby trinket shop. “It is a disrespect. Everybody’s faith in the temple will go away.”

As the sun sets in Puri, a throng of devotees climb the temple’s broad, stone steps, where a man ushers them in by tapping their heads with two slender sticks, a transfer of the deity’s blessings.

Inside the temple, priests squat to light oil lamps. Flanked by pillars covered in brightly coloured motifs, thousands of men and women throw up their hands at the sight of a life-size statue of Lord Jagannath. Nearby, the entrance to the vault is shrouded in darkness behind metal bars.

Sonalata Das, 67, a bespectacled woman in a brown silk sari, lingers with clasped hands in front of a painting of Jagannath. Asked about the missing keys, her face hardens.

“I prayed that God would completely finish off the person who has fooled around with the key for his wealth,” she says. “May he be destroyed.”