Manchester City owner’s new yacht would be 482-foot, the longest in the world. As the brother of Abu Dhabi’s ruler, dignitaries were invariable visitors. One helicopter pad was too few – it needed two.

By the time it hit water in 2012, the Topaz was the fourth-largest superyacht in history. Things were going well for Mansour, the deputy prime minister of Abu Dhabi. That summer, his City team won the Premier League for the first time. Over the next 12 seasons, they would win a further seven league titles, plus another 11 major trophies.

Mansour enjoyed much of that success from his yacht’s eight floors. Leonardo DiCaprio used the boat during the 2014 World Cup and was photographed throwing luxurious parties off the Brazilian coast.

Yet by 2016, the funding of the Topaz would see him implicated in a $4.5 billion (£3.4bn) scandal that a US judge called “one of the biggest financial crimes in the history of the world”.

It left a former Malaysian prime minister in jail for the systematic embezzlement of funds from the country’s sovereign wealth fund and two of the sheikh’s closest lieutenants, American-born Aabar CEO Mohamed Al Husseiny and Emirati businessman Khadem Al Qubaisi, imprisoned in the United Arab Emirates. They and Mansour were among those named by US investigators as “co-conspirators” in what the Department of Justice (DOJ) labelled its “largest kleptocracy case to date”. No charges were ever brought against Mansour.

In the international fallout from the scandal, IPIC, the $70 billion sovereign wealth fund Mansour operated, was wound up, and a claim made in court that “the sheikh would not get out of bed for less than $100 million” caused intense embarrassment.

Now, a decade on from what would become known as the 1MDB scandal, Mansour faces another reckoning.

Last month, an independent panel ruled that City had profited from more than £920 million in overstated revenues and understated expenses across nine seasons from 2009-10 to 2017-18. The judgment centred on the claim that Mansour’s company, Abu Dhabi United Group (ADUG), had illicitly disguised equity injections as sponsorship.

City continue to deny any wrongdoing and have lodged an appeal. Whatever happens next, however, it is undeniable that scandal is at Mansour’s door again.

Analysis of Manchester City as they extended their winning start to the season with victory over Ipswich at the Etihad Stadium.  In the early 2000s, Khaldoon Al Mubarak was introduced to a Malaysian fixer named Jho Low.

Al Mubarak is the most visible Emirati representative at Manchester City, the chairman who holds the ultimate sign-off on key decisions. But even 20 years ago, Al Mubarak was already an influential figure in the UAE. As an aide to Mohammed bin Zayed (MBZ), Mansour’s brother and ruler of the UAE, he already ran Mubadala Investments, a sovereign wealth fund intended to diversify the Gulf state’s reliance on oil. He remains a key confidant of both MBZ and Mansour.

According to testimony under oath, it was on Al Mubarak’s advice that Low launched a sovereign wealth fund, 1MDB (1Malaysia Development Berhad), which would later be used by the then-prime minister and others as the vehicle for a multi-billion-dollar fraud.

“Based on Khaldoon’s feedback, it was proposed that TIA (an existing state wealth fund) be changed to 1MDB, identical to the concept of Mubadala Development in Abu Dhabi,” former 1MDB CEO Shahrol Halmi told a Kuala Lumpur Court during the 2019 trial of former Malaysian prime minister Najib Razak.

According to the authors of Billion Dollar Whale, a book investigating the 1MDB scandal, it was also originally through Al Mubarak that Low developed relationships with two men who would become key figures in his scheme – Mansour’s fixers Al Husseiny and Al Qubaisi.

In 2011, 1MDB began working with Aabar, an Abu Dhabi-based investment firm that started sponsoring Manchester City in 2010 and was owned by IPIC, Mansour’s sovereign wealth fund. Aabar’s CEO was Al Husseiny.

DOJ prosecutors outlined details of how the fraud would operate during their successful conviction of several individuals involved in the scheme, including Roger Ng, a Goldman Sachs banker. He would eventually be sentenced to 10 years in prison for violating US anti-bribery laws, money laundering and illegally skirting his company’s accounting controls.

In 2012, Low proposed that Goldman Sachs sell $3.5billion of bonds on behalf of 1MDB, which would then make investments in several coal-fired power plants. The Malaysian fund planned to combine these plants into one company, making them more valuable, before publicly listing the new consolidated venture on the stock exchange, where 1MDB stood to earn $5bn.

The issue was that a deal of this size needed guaranteeing – the fledgling fund had never issued dollar bonds to international investors and did not have a credit rating. This is where Mansour came in.

Low’s plan was for IPIC, which had profited from an oil boom, to guarantee the Goldman Sachs bonds. But what would be in it for IPIC?

Speaking to the DOJ under oath during US proceedings, another Goldman Sachs banker, Tim Leissner, revealed a tool that he said would be used to motivate IPIC. Leissner would later be sentenced to two years in federal prison after admitting his role in the fraud.

Describing a meeting in London which took place in early 2012, around a month before a planned meeting with Sheikh Mansour, Leissner recalled Low sketching a series of boxes on a piece of paper.

“On one side of the page were several boxes for Malaysian officials who needed to be paid off, and on the other were boxes for the Abu Dhabi officials,” he said in testimony before the District Court for the Eastern District of New York.

Leissner subsequently delivered the most significant piece of testimony – that Low had “said the sheikh would not get out of bed for less than $100 million.” The implication was, Leissner believed, that to secure IPIC’s guarantee of the bonds, Mansour would need to be paid.

Low and Leissner travelled to Abu Dhabi to meet Mansour and broker the deal. According to Ng’s defence testimony, Low “discussed delivery of a letter to Sheikh Mansour that would help secure IPIC’s involvement”. The deal was agreed and signed – IPIC would guarantee 1MDB’s investment.

Soon after, more than $1.3 billion, traced by DOJ investigators, was paid into a firm named Aabar-BVI’s account by 1MDB. The issue was that Aabar-BVI was not legally a part of Aabar, but an imitation firm in Al Qubaisi’s and Al Husseiny’s names.

“It was as if the chief executive of General Electric or another blue-chip American firm, had set up a fake company to look like General Electric to engage in off-the-books fraudulent behaviour, while still enjoying the cover of a well-known name,” wrote authors Tom Wright and Bradley Hope in Billion Dollar Whale.

• A Tell Media report / Originally published in The Athletic