Image copyright Enrique Botello Image caption The Teachers Group luxury compound in Mexico

A charity that has been paid millions by the UK government for its work in Africa is under the control of a cult-like organisation, an investigation by the BBC and US partners has revealed. The group's senior leaders - wanted by Interpol - are thought to be holed up in a luxury coastal compound in Mexico.

Patrick Goteka was working for a charity in Zimbabwe when, in 2006, his employer offered him a big break - the chance to transfer to the US.

Goteka, who would be working as a manager in the recycled clothes business, knew the move would mean sacrifices - separating him from his wife and three children. But he says he didn't bank on also having to join a cult-like organisation - the Teachers Group - and surrender a chunk of his monthly salary when he took on his new role.

Media playback is unsupported on your device Media caption Patrick Goteka: "They told me - you will get to visit your family once a year."

Goteka thinks back to the conversation he had at the time.

"They said, 'We cannot send someone who is not in the Teachers Group.' So they said: 'You should join.'"

He also remembers being told he would be making a good living.

"We are going to support you when you are sick," they said. "We'll support your family. We'll give you good conditions."

There was no big initiation ceremony. No documentation. They just shook hands and, with that, Goteka had been inducted into the Teachers Group.

UPDATE: The UK's Department for International Development (DfID) has issued a statement saying that payments to Dapp Malawi have been suspended while the allegations in this story are investigated.

The organisation Goteka found himself joining had been set up in Denmark in the early 1970s by a man called Mogens Amdi Petersen.

For years the Teachers Group has run a government-funded alternative school system, but in 2001 the Danish authorities raided its offices and charged Petersen with fraud. Found not guilty in 2006, he and some of his associates immediately left the country, but prosecutors appealed and the group are now wanted by Interpol. It's thought they may have taken refuge in a massive luxury compound, worth an estimated £20m ($26m), on the Pacific coast in Mexico.

Image copyright Scanpix Image caption Petersen, 77, is wanted by Interpol

This is just one part of the Teachers Group global network, which includes offshore companies and commercial ventures. It is also behind Dapp Malawi - the Malawian branch of a charity, Development Aid from People to People - which employed Goteka after his return from the US.

Dapp runs education, health and agriculture projects in Malawi, and has received tens of millions of pounds in the last decade from Unicef, the EU and the UK's Department for International Development (DfID).

Part of these funds will have been used to pay the charity's staff. But as the experience of Goteka and others reveals, a proportion of the money paid to some staff eventually finds its way to the Teachers Group.

Once in the US, Goteka was introduced to the next stage of the Teachers Group philosophy - the "common economy". This is a fund which all members are expected to contribute to. Goteka says he ended up paying 50% of his salary, much of which he would otherwise have sent back to his family in Zimbabwe.

Find out more

The organisation calls these payments "voluntary" but Goteka says employees are really left without a choice.

"If you write more money to your wife they will say, 'Cancel this and start again.' People were crying when they were making those budgets. It was just a shame."

Dapp Malawi didn't want to be interviewed and responded to our questions through a British law firm. It says there are Dapp Malawi staff who are members of the TG but says "this is a private matter for them, it has nothing to do with donors, whose funds are not applied to TG".

It's not just money that the Teachers Group demands of its members - but also their spare time.

Christopher Banda is a smiling but earnest young field officer for Dapp in Malawi. He is also a member of the Teachers Group, having joined in 2009 because, he says, "it was like my job security".

"We call ourselves comrades... and we share the private life together," says Banda, referring to what is known in the group as "common time". This is personal time Teachers Group members are required to give up for the benefit of the organisation, for example to help maintaining buildings.

"In the common time we are always together," says Banda. "We only get a chance one weekend a month to visit our family."

Image caption Christopher Banda told Unicef about Dapp's links with the Teachers Group

It was while running a Dapp project to improve sanitation in villages in Malawi, that Banda raised the alarm about the charity's links with the Teachers Group. The project was being jointly funded by DfID and Unicef - the UN children's charity.

Banned, he says, from talking to donors about the project, he was one of a group of field officers who wrote to Unicef in May this year about a number of concerns, including employees' contributions to the Teacher's Group.

We introduced Banda to Patsy Nakell from Unicef. As she hears his tale she looks increasingly perturbed, before concluding: "I've never seen any such thing in my life before, and I don't understand the logic behind this, it just is bizarre."

She adds that if it's true that some of Banda's Unicef-funded wage was deducted to be sent directly from Dapp to the Teachers Group "then it's unacceptable, it's abhorrent".

The alarm bell sounded by Banda and others has already had an effect, with Unicef pulling all its funding from the Dapp project he was working on in Malawi at the end of June. Unicef is now conducting a full audit of the project and is reviewing other contracts with Dapp in Africa.

Dapp told us: "At no time has Unicef ever raised with Dapp Malawi concerns over deductions from salaries of TG members."

What is Dapp?

Dapp Malawi is part of a global federation of charities called Humana People to People, which has its headquarters in Zimbabwe

The organisation has more than 30 different members around the world - there is a Dapp UK, a Dapp Zambia, Humana People to People Brazil, and so on

Dapp is one of the major NGOs active in Malawi, providing a range of aid projects from farming to health and education

Evidence uncovered by the BBC proves that these contributions are not confined to just a few people, such as Banda and Goteka.

In his small office, Harrison Longwe, an accountant at Dapp in 2014 and 2015, pulls out a laptop and shows me a spreadsheet with the names of more than 700 Dapp employees in Malawi. For a quarter of them there's a column with additional deductions.

"This is what goes to TG [Teachers Group] direct," Longwe explains. "Some would be contributing as high as 30% to the TG."

Of those sending money to the Teachers Group, the average contribution was 25%.

It's astounding when you consider that the average monthly salary in Malawi is just £60 ($80). Few of those employed by Dapp could have easily afforded to part with any of their salary, let alone a quarter of it.

Image caption Dapp's teacher training college in Blantyre, Malawi

In a statement Dapp denies "that it demands contributions from staff for membership of TG, that it pressurises employees to contribute to TG" or it makes any deduction from salaries other than "per instruction by the individual employee".

While the Teachers Group started in Denmark and is recruiting in Africa, the centre of its orbit now is the luxury coastal compound at San Juan de las Pulgas in Mexico, 150 miles south of Tijuana.

Teachers Group

The Teachers Group is the inner circle of a movement known as Tvind, founded by Mogens Amdi Petersen in the early 1970s

It is linked with schools and teacher training colleges, charities, and businesses - including plantations in South America

Some of the charities in the US and Europe collect second-hand clothes

The BBC reported in 2002 that Danish police had estimated Petersen's wealth at £100m

Banda was one of the chosen ones sent there. It is a stunning vision of polished stone and bright white cathedral-like buildings with a futuristic feel. Designed by a renowned Danish architect, it has been described as a combination of Disney World, Club Med and the Taj Mahal.

Banda was ostensibly there for a conference about agriculture, but he says it was nothing of the sort.

"Most of the times we were busy in the class discussing about how we can protect the Teachers Group," he says.

Goteka has also been to the Mexico compound.

"It's quite beautiful, most of the materials are imported, it's just a different type of furniture, beautiful and expensive," he says, recalling his visit.

Like Banda, Goteka met Petersen in Mexico. He knew him personally, because Petersen had hired him to search for his lost dog - for two years - when it went missing in Zimbabwe in 1998. It was afterwards that he started working with Dapp Zimbabwe, and later for Dapp Malawi.

When we meet in Malawi, Goteka takes me to see one of Dapp's teaching colleges, called Amalika.

Like many of the Dapp sites it is remote, lying at the end of a single-track road bordered by towering bluegum trees and dense forest. Goteka was a campus manager at the college, which, he says, was a recruiting ground for the Teachers Group.

"When students are done here they are persuaded how nice TG is so they can join," he says.

It's what happened to a teacher we meet later. He is nervous and will only chat inside our car, where he can't be seen. He joined the Teachers Group three years ago and voluntarily pays contributions out of his government salary.

"You feel a commitment to them, even though you don't know where the money is going," he says.

The TG philosophy is, he says, "Forget about your family - think about Teachers Group."

He adds: "It's like you have sacrificed the whole of your life, 100% in Teachers Group."

Image caption A manual used by the Teachers Group outlining the organisation's philosophy

Speaking to him one gets a sense of the cult-like nature of the group especially when it comes to dissent.

"It's automatic. You are in a private meeting… and they try to make you to agree to their side."

There is no need for force, he says. "Those people are intelligent. They try to explain to you... so you agree to say, 'Ah, thank you very much. Now I'm agreeing. I didn't understand it.'"

We have discovered that he is one of 90 government teachers in Malawi who are also Teachers Group members - and that Teachers Group has a target to recruit 400 teachers from Dapp's teaching colleges in Malawi.

One of the colleges used as recruiting grounds was built with £2m ($2.6m) from DfID.

We left Patrick at the bus station for his long journey back to his home in Zimbabwe.

He said he hoped the BBC's work would bring change to Dapp.

"I just feel embarrassed, I cannot imagine they [Teachers Group] still exist in our continent and all over the world."

DfID told the BBC: "We will not hesitate to act in any situation if wrongdoing is proven. DfID welcomes any evidence and documentation that the BBC can send us in order to investigate these serious allegations."

We are taking our evidence to DfID and other donors who have the power to investigate further and make sure aid money is all used for the benefit of the people who need it most in Malawi.

UPDATE: The UK's Department for International Development (DfID) has issued a statement saying that payments to Dapp Malawi have been suspended while the allegations in this story are investigated.

Follow @BBCNewsMagazine on Twitter and on Facebook