Her husband, a Commonwealth Bank executive in Canberra, has been cleared in a internal bank inquiry of using his position at the bank to advance the Nigerian oil deal.

The deal, to export huge volumes of oil into Asia, unravelled amidst an intriguing web of African politicians, Asian buyers and a Nigerian "man of god".

Although the former business partners, from Queanbeyan, said they lost $100,000 in the ill-fated venture, there is no suggestion the Canberra couple James and Sylvia McCourt ever profited from it.

Separately, the former businesses partners have accused Sylvia McCourt of fraud over their dealings with her, an allegation that is being investigated by NSW police.

Sylvia McCourt is a former corporate account manager for the Commonwealth Bank in Canberra, with a specialty in business banking and diplomatic relationships, according to her Linked In profile.

Her husband James specialises in property development and investment finance for the bank, according to Linked In.

ASIC records show James Ross McCourt, 43, as the sole director of Amira International Solutions, a business that has said it "consistently traded" millions of barrels of oil each day.

In emails, Sylvia McCourt has described herself as Amira's chief operating officer.

"Amira has evolved strategically to become one of the world's leading independent commodities trading houses," the company's website read until about September 2017 when it was taken down.

Amira International Solutions should not be confused with AMIRA International Ltd, an unrelated industry body for Australian mineral companies based in Melbourne.

Documents given to NSW Police by the two Queanbeyan business partners involved in the deal described how the McCourts approached potential business partners about two years ago with a lucrative oil trading proposal.

The proposal was to break into the Nigerian oil market, with the promise of a handsome return for every barrel exported into China.

According to emails and other correspondence, Amira would act as the middleman between Asian buyers and a Nigerian oil company named in bank records as KKI Global Enterprises.

Joseph Tobore, a Nigerian who said he was a politician referred to in correspondence as "The Honourable", was also involved in smoothing any problems on the ground through his business Gab-Josac and Sons.

"As Hon mentioned, a lot of funds have been spent on securing and ensuring the product is allocated… including our own funds," Sylvia McCourt wrote to Amira's business partners in the middle of the deal.

"Please be patient a little longer while I am trying my hardest to get this concluded for all of us."

Investors were told that as many as eight million barrels of oil were available for export, with Mr Tobore acting as a fixer to address any snags on the government's side.

All they needed to do was pay $50,000 USD to cover the cost of the "dip tank authorisation" process, the final hurdle in the exporting chain.

Australian bank records show that one Australian paid at least AUD$74,000 into the Nigerian bank account of KKI Global Enterprises.

On bank records of the transactions to the Nigerian accounts, it was stated that the "funds are clean and clear, of non-criminal origin and payable in cash".

When suspicions grew about the oil seller's repeated demands for extra cash, Sylvia McCourt tried to soothe her now-estranged business partners.

"Yes, they still need that 50K, but they agreed to put it in a letter that will be the last 50K and no more payment is needed," she wrote in a text message in June 2016.

Mr Tobore told Amira in August 2016 that he would pull some strings within the Nigerian president's office to get the stalled deal back on track

"My contact in the presidency wants the protocol attache to get in touch with embassies and will put a call across to the [oil company's] commercial manager soon," he said in a message forwarded from Sylvia McCourt to investors.

By June 2017 the proposed Korean buyer of the Nigerian oil, frustrated by requests from Nigeria for more money, had written to Amira to raise questions about the proposal.

Above a signature describing themselves respectively as Amira's chief executive and chief operating officer, James and Sylvia McCourt replied.

"I [no] longer care whether you believe it is real or not," they wrote.

"Come at me [sic] as hard as you like, we have nothing to hide and in fact we provided you far more information and reassurance than should ever be required in a transaction of this nature."

The snag was that the Korean oil buyers - and Chinese buyers approached subsequently in a second attempt to broker a deal - had doubts about whether the Nigerian companies were legitimate enterprises and, according to documents provided to police, soon went cold on the deal.

The Nigerian National Petroleum Company is a legitimate state-owned enterprise that manages the country's contracts for oil export.

Just 11 foreign companies hold contracts with the Nigerian National Petroleum Company to export oil from Nigeria, with a per-company limit of 32,000 barrels per day.

Amira International Solutions is not one of these 11 companies, nor is KKI Global or Gab-Josac.

Records and correspondence obtained by Fairfax Media reveal inconsistencies in KKI Global's claims about its business.

Bank records list KKI Global's address as the Primose Tower block in the heart of the financial district on Nigeria's Lagos Island.

But files kept by Nigeria's Corporate Affairs Commission list KKI Global's address 15 kilometres away in an inner-city back alley.

Company records traced the business back to a Nigerian man called Kenneth Isaac, who variously claims to be a doctor and a pentecostal preacher.

When approached by Fairfax, Mr Isaac maintained KKI Global was a legitimate company and he threatened "divine disaster" on anyone who would suggest otherwise.

"Kindly let us know if there is any buyer worldwide who signed a contract with us and issued a bank instrument or gave logistic funds and we have failed to give him product," he said.

"If not, any person, a buyer, or company who [made such claims] may face divine disaster.

"I am a man of God living with divine covenant," he added.

He also said he had no knowledge of any deal with Amira.

Mr Tobore did not appear to be the political fixer he claimed to be in his correspondence, nor did his Gab-Josac business live up to its claims.

Gab-Josac lists its headquarters at Nigeria's affluent Victoria Island, but government filings trace the business back to a corrugated iron shack on the outskirts of Lagos.

There are no public records of Mr Tobore ever holding political office in Nigeria.

Mr Isaac said KKI Global did have a business relationship with Gab-Josac and Mr Tobore.

Mr Tobore did not reply to Fairfax Media's requests for comment.

There is no suggestion Amira International Solutions and the McCourts were aware of the status of their Nigerian contacts and no suggestion the McCourts profited from the affair.

The now estranged business partners who have complained about the deal and lost money still believe the McCourts were trying to set up a genuine business as oil brokers, but believe their money, not the McCourts, was being used to land the first deal.

NSW police became involved in mid 2017 after a complaint from the former business partners of the McCourts about an unrelated issue.

Documents provided to NSW Police by the estranged business partners said that, with the Nigerian deal in the works, Sylvia McCourt requested $17,500 from them for a separate business matter.

A flurry of emails sent to a bank on May 19, 2017, alleged this money was never put to the purpose Sylvia claimed, and was instead used to pay off personal debts.

NSW Police issued the following statement in response to Fairfax Media enquiries about Sylvia McCourt.

"Monaro Local Area Command are investigating a fraud matter that allegedly occurred on 19 May 2017," police said.

"As the investigation is ongoing, no further information is available."

Amira International Solutions has spruiked its connections within the international oil trade on its website.

"We source crude oil and refined oil products from more than 100 countries, and work with more than 75 global financial institutions, balanced across Asia-Pacific, the Americas, the African, the Middle East and Europe," the website read.

"Amira has crude oil trading specialists in offices around the globe — with our primary trading operations in Shanghai, London, and South Africa."

Fairfax Media could not find any publicly listed records for Amira offices in Shanghai, London or South Africa, nor could it locate the company's headquarters on Canberra's Northbourne Avenue.

Amira also claimed on its website that it has been operating since 2007, despite company records showing it was registered in 2015.

Amira took its website down when questioned about these claims and the account has since been suspended.

James McCourt declined to comment on his involvement with Amira International Solutions when contacted by Fairfax earlier this year.

"No I can't come and have a chat to you in regards to anything like that. No," he said.

"It's not anything I wish to discuss with you."

Sylvia McCourt refused to answer a series of emails and letters from Fairfax Media about her involvement in Amira.

Commonwealth Bank told Fairfax it had conducted its own internal investigation into allegations that Mr McCourt had used his position with the bank to influence the foreign oil deal.

"We seriously consider any concerns raised with us regarding the behaviour of our employees as representatives of Commonwealth Bank," a statement from the bank said.

"In this instance we investigated allegations made of inappropriate influence, and found these allegations to be unsubstantiated."

Sylvia McCourt left the bank before her involvement in Amira, and there is no suggestion she used her former position to influence the deal.