It is one of the world's greatest financial scandals.
Billions of dollars from a state fund meant to help the Malaysian people went missing, disappearing into the shadows of the global financial system.
According to US and Malaysian prosecutors, the money lined the pockets of a few powerful individuals and was used to buy luxury real estate, a private jet, Van Gogh and Monet artworks - and to finance a Hollywood blockbuster.
Outcry over the alleged looting of 1MDB has reverberated around the world, with authorities in at least six countries probing a vast web of financial transactions stretching from Swiss banks to island tax havens to the heart of South East Asia.
The scandal even led to the toppling of the political party that governed Malaysia for all of its history as an independent nation.
Goldman Sachs, one of Wall Street's most powerful banks, is facing criminal charges in Malaysia - which it says it intends to vigorously defend. Meanwhile a fugitive playboy charged in the US and Malaysia remains on the run - his infamous $250m luxury super yacht now in the hands of authorities.
All eyes are now on the Malaysian capital Kuala Lumpur, where former prime minister and ex-chairman of 1MDB's advisory board Najib Razak is on trial in the first of several cases against him.
The cast of characters around the 1MDB scandal paints a picture of a truly global saga - from the journalists who doggedly followed the money to the international elite alleged to have profited.
At the centre of this story is Malaysia's former prime minister: the once untouchable man who set up a "bold and daring" sovereign fund in 2009 to propel his nation's economic development - only to see it bring him and his political dynasty down in disgrace nine years later.
To truly understand Najib Razak is to examine his roots. The eldest son of Malaysia's second prime minister, Abdul Razak, and also the nephew to its third, he descends from political aristocracy. When he finally became prime minister in 2009 - as the head of the party which dominated Malaysian politics for half a century - it seemed he was finally taking a pre-ordained role.
An Anglophile, Mr Najib completed his secondary school education at the UK's Malvern College, a prestigious private school, before studying industrial economics at the University of Nottingham.
That background and his rhetoric about the importance of "moderate" Islam made him a natural fit with Western contemporaries including David Cameron and Barack Obama.
But there were clouds above him from the very beginning of his premiership. Questions over a French submarine deal made in 2002 when he was defence minister dogged the new PM. It was alleged that some $130m in kickbacks had been paid as part of the $1.2bn deal - which Mr Najib has always denied.
The grisly murder of a Mongolian model who served as an interpreter for the submarine deal raised further questions. A French investigation continues while the new Malaysian government recently re-opened its probe. Mr Najib insists he never met the woman.
Najib Razak established 1MDB in 2009 as a way to manage resource-rich Malaysia's wealth with strategic investments. Major red flags were raised in 2015 when it missed payments due for some of the $11bn (£8.3bn) it owed to banks and bondholders - although investigators and journalists had long been on the case.
In July 2016 the US Department of Justice filed a civil lawsuit alleging that more than $3.5bn had been plundered. (It later upped the figure to more than $4.5bn.)
"A number of corrupt officials," said then-US Attorney General Loretta Lynch, "treated this public trust as a personal bank account".
The lawsuit named alleged perpetrators but left a "Malaysian Official 1" unnamed. MO1, later confirmed to be Najib Razak by his own government, was alleged by US prosecutors to have received $681m in stolen funds but to have returned most of it.
He was cleared of all wrongdoing by Malaysian authorities while he was in office but after his party's shock defeat at last year's general elections, the tide has dramatically shifted.
Several of his apartments were raided and police seized a trove of luxury goods and $28.6m (£21.3m) in cash. There are currently 42 charges levelled against him for alleged corruption, money laundering and abuse of power. He has pleaded not guilty to all charges and maintained his innocence - including through a soul ballad performed by him and a choir.
The spending habits of Najib Razak's wife have been compared to those of Imelda Marcos and Marie Antoinette. Since her husband lost power, Rosmah Mansor, 67, has been formally charged with money-laundering and tax evasion, to which she has pleaded not guilty.
Ms Rosmah's expensive tastes have been widely mocked in Malaysia, where she is harshly criticised for being out of touch with ordinary people who struggle to make ends meet. In 2018, very public police raids on properties linked to her and her husband lit up social media as images of supermarket trolleys packed with more than 500 luxury handbags, hundreds of watches, and 12,000 items of jewellery said to be worth up to $273m confirmed Malaysians' suspicions that their first family had been living wildly extravagant lives.
With Rosmah Mansor's larger than life persona and much noted penchant for Hermes Birkin bags, her court appearances are highly scrutinised.
"She isn't rude but she also isn't particularly friendly or bubbly. In person, she comes across as being imperious," says Reuters news agency's Malaysia correspondent Rozanna Latiff. "On days Rosmah Mansor is called in for questioning, there is a lot of interest in her outfits and bags."
It's a political comeback story like no other: at 93, Mahathir Mohamad, the man who dominated Malaysian politics as prime minister in the 1980s, 1990s and early 2000s, is back in form and leading Malaysia.
His return to the political fray was motivated by one clear desire - to unseat Najib Razak, his former protégé.
"I apologise to everyone, that I am the one who elevated him, the biggest mistake in my life. I want to correct that mistake," Mr Mahathir said on the campaign trail in early May 2018 after defecting to the opposition to take on Mr Najib.
A few days later he shocked the world by defeating his former party, which had run Malaysia for more than half a century.
Mr Mahathir's return has resonated well with Malaysians, many of whom champion their new government's efforts in bringing those who allegedly looted 1MDB to justice. But political observers note that the elderly statesman not only paved Mr Najib's path to power but also stood accused of authoritarianism during his own long tenure at the top.
A Chinese-Malaysian financier from the bustling island of Penang, Low Taek Jho - more famously known as Jho Low - is portrayed by Malaysian and US investigators as one of the masterminds of the 1MDB scam.
Despite never holding a formal position with the fund, he is alleged to have played a crucial role in its activities. And it was his savvy networking and shrewd business sense that allowed him to thrive, say journalists Bradley Hope and Tom Wright in their 2018 best-seller Billion Dollar Whale, which recounts Jho Low's alleged exploits.
"Jho Low is the most interesting person in the 1MDB affair, a mysterious master of ceremonies," Hope told the BBC. "It became clear very early on he was the connecting point between everyone involved in the 1MDB fund - and the only one with a 360-degree view of the multi-billion dollar scheme."
US prosecutors say Mr Low leveraged his powerful political connections to win business for 1MDB through the payment of hundreds of millions of dollars in bribes. Billions, they say, were laundered through the US financial system and used to buy some of the world's most expensive real estate, coveted artwork, and finance Hollywood films.
This was a man known for mixing business with a great deal of pleasure. Lavish parties and high-profile friendships with Arab royalty and A-list celebrities fuelled his quick rise to the top. Britney Spears even popped out of his birthday cake at a 2012 Vegas bash.
The reporters speculate in their book that at one point, Jho Low may have had access to more liquid cash than almost anyone else on earth.
But the fall of Najib Razak's government proved to be bad news for Mr Low. Criminal charges were filed and he is now wanted in several countries. His current whereabouts are unknown but he maintains his innocence through statements on his official website. His lawyers say he cannot get a fair trial in Malaysia.
"Jho Low is driven but he is also both meticulous and terribly sloppy. He was frantically building an empire with money that wasn't his and in the end, his whole scheme became desperate and unsustainable," Hope said.
This slick German banker represented one of the world's most powerful financial institutions, Goldman Sachs, at a time that the bank was charging into Asia.
In the aftermath of the 2008 financial crisis, Timothy Leissner's deal-making in South East Asia (Malaysia in particular) netted the bank significant revenues and he rose to become the company's chairman in the region.
But the biggest deals would come when he crossed paths with Jho Low - alleged to be the power player behind 1MDB.
Goldman had previously rejected Mr Low as a client, after compliance officials raised concerns about the source of his money. But, according to a US indictment, Mr Leissner and another Goldman banker, Roger Ng, used Mr Low's powerful connections to obtain business for Goldman.
The bank is alleged to have earned an eye-popping $600m in fees for arranging and underwriting three bond sales to raise $6.5bn for 1MDB in 2012 and 2013.
Mr Leissner has pleaded guilty to US charges of conspiring to launder money and violating anti-corruption laws by bribing foreign officials.
Malaysia has also filed charges against him, Mr Ng and 17 other former and current Goldman bankers. The bank itself has also been charged.
Goldman Sachs denies wrongdoing. It has called the Malaysian charges against it and the 17 people "misdirected" and vowed to "vigorously defend them". It has sought to portray Mr Leissner, who it suspended in 2016, as having gone rogue and has apologised for his behaviour.
But the Malaysian government has rejected the apology and called for the bank to cough up $7.5bn in reparations. Mr Ng, who left Goldman in 2014, denies all the charges against him.
Money talks but does the power of celebrity speak louder?
The 1MDB scandal hasn't just been about powerful politicians and financiers: fugitive businessman Jho Low often partied with Hollywood's A-list.
None of them are accused of any wrongdoing whatsoever, but their social connections with Mr Low have been the subject of media reports.
That Leonardo DiCaprio movie
The Oscar-winning actor starred in 2013's The Wolf of Wall Street, co-produced and financed by Riza Aziz, son of Rosmah Mansor and Najib Razak's step-son. The Martin Scorsese film about greed and corruption bagged DiCaprio a prestigious Golden Globe award for Best Actor - and he thanked both Mr Aziz and Mr Low by name in his acceptance speech.
US prosecutors said misappropriated 1MDB money was used to finance the film, and the production company Red Granite paid $60m to settle a civil lawsuit with the US government. The company denies any wrongdoing.
But Mr Aziz was arrested in Malaysia in July 2019 and faces trial on five charges of money laundering. He is alleged to have received nearly $250m of misappropriated 1MDB funds. He has pleaded not guilty to all charges.
DiCaprio, meanwhile, has pledged to assist US authorities and has handed over a Picasso painting allegedly gifted to him by Mr Low.
Musician friends Kasseem Dean (aka Swizz Beatz) and Alicia Keys
The ambitious record producer and his superstar wife were once part of Jho Low's inner circle, often photographed at his notoriously swanky parties. Dean performed at Mr Low's infamous 31st birthday celebrations (the one with Britney in the cake).
The musician is also credited with introducing Mr Low to the moneyed art world, where he is alleged to have bought works including a Van Gogh drawing and two Monet paintings with 1MDB funds.
Partying with Paris Hilton
Another member of the famed inner circle, the hotel heiress reportedly met Mr Low in 2009. They were often seen together in paparazzi pictures (and selfies), partying it up around the world - from the gambling tables of Vegas to the ski slopes of Whistler and balmy Saint-Tropez.
Romancing Miranda Kerr and Elva Hsiao
What do an Australian supermodel and a Taiwanese singer and actress have in common? Both women were once linked to Jho Low.
After a series of extravagant dates (including sailing around Europe for 10 days) Mr Low showered Miranda Kerr, one of the world's highest-paid supermodels, with out-of-this-world gifts: an acrylic, see-through grand piano (worth up to $1m) and an 11-carat diamond necklace and matching earrings. She has since turned over millions in jewellery to US prosecutors.
Mr Low took Taiwanese singer Elva Hsiao on a million-dollar date to Dubai, where they dined on a private beach, according to Billion Dollar Whale.
The 1MDB saga would never have come to light without the tenacious work of journalists who pursued the story for years, breaking bombshell after bombshell and forcing the fund's dealings into scrutiny.
Clare Rewcastle-Brown, The Sarawak Report
More than a decade ago this Malaysian-born, British journalist began investigating Malaysia's political elite from her kitchen counter in London after putting the kids to bed. Her Sarawak Report website was initially focused on shadowy dealings in one Malaysian state. But when one of 1MDB's early deals was made in Sarawak, her attention began to shift to what seemed like "a highly suspect outfit".
At the end of 2013, she received a tip-off that Najib's step-son had produced The Wolf of Wall Street. "That's when I started digging," she says. "Just really because I couldn't resist such an obviously significant story." As she followed the money trail, the scoops began to roll in, captivating Malaysians whose domestic media were mostly unable or unwilling to pursue the story.
In early 2015, Rewcastle-Brown received a trove of more than 200,000 documents from Swiss whistleblower Xavier Justo and made a stunning allegation: that $700m had been dropped directly into a bank account belonging to a Jho Low-controlled company as part of a 1MDB deal.
A few months later - under the headline "SENSATIONAL FINDINGS!" - she published details alleging that nearly $700m had been deposited in the prime minister's bank accounts in 2013. The Malaysian authorities blocked her website and issued a warrant for her arrest.
"I had people all over the world who would contact me with information. Obviously it would be my job to stand it up if I could," she said. "At the height of this there were people being hired to muscle me in London, follow me and photograph me... I had to go to the police."
Tom Wright and Bradley Hope, The Wall Street Journal
Their 2018 offering Billion Dollar Whale meticulously detailed Jho Low's alleged exploits and became an instant bestseller in Malaysia.
But Tom Wright and Bradley Hope have been investigating the 1MDB money trail for years at the Wall Street Journal.
"News stories don't typically go beyond 2,000 words and it felt like we were cutting out a lot of fascinating details [from the saga]," said Hope. "We knew people were having a hard time following the scandal and there was a bigger, more colourful story to do about Jho Low specifically."
Hope said their book crystallised how bad the scandal was for Malaysia.
"There was so much noise and misinformation out there," he said. "To see it all laid out in one place, fact by fact, made it very clear that 1MDB had become one of the world's biggest financial scandals. Billion Dollar Whale shows how it developed chronologically and brought the issue home for many Malaysians."
The book may have also increased global pressure in the search for Jho Low (now wanted in several countries).
"Readers have sent us letters and politicians [Prime Minister Mahathir Mohamad and Finance Minister Lim Guan Eng] have even used and referenced our book to explain the issues surrounding 1MDB," Hope said. "Billion Dollar Whale is starting to filter through around the world and people who have never heard of 1MDB tell us they were utterly engrossed by it."
The Edge Malaysia
If you read nothing but Malaysian newspapers and only watched local TV news reports at the height of the 1MDB scandal in 2015, you'd be fooled into believing all was well in the country. Malaysian journalists and editors learned quickly that reports about the sovereign fund's scandals courted danger and would risk their operating licences.
But there were those who persisted and paid the price. The Edge Media Group was one.
The Edge's newspapers published investigations into 1MDB's activities and had its newspapers' publishing licences suspended over what was deemed as "reporting that could affect public order".
"This is nothing more than a move to shut us down in order to shut us up," publisher Ho Kay Tat said at the time.
Leading the charge against 1MDB in Malaysia is lawmaker Tony Pua, who raised constant questions while in opposition under Najib Razak's government.
His party is now in power but Mr Pua remains unashamedly vocal in his disdain for the former PM.
"Najib Razak is the ultimate culprit. When confusion arises over his statements I will pop in to steer things in the right direction," he told the BBC on the sidelines of a visit in Singapore.
Also political secretary to Malaysia's finance minister, who is leading 1MDB investigations, Mr Pua said he remains focused on "fixing damage done to the economy".
"The financial scandal is in the past and there are no more shenanigans, it's the clean-up process now," he said. "We need to bring about economic growth and closing the 1MDB chapter is a big part of that."
The colourful politician, who hails from Johor state, often takes to YouTube to lament the scandal. "I know the facts and I articulate them," he said. "I get information from documents and informants and piece them together to tell the story of what's actually happening."
But he says Mr Najib's trials are "just the beginning" and the judicial process could go on for years. "The jigsaw is almost complete but there are a few missing pieces. And I believe Najib Razak's trial will reveal some."
Najib Razak is expected to face several trials in Malaysia. If found guilty of the many offences he is charged with, Mr Najib could spend decades in prison. Jho Low remains at large.
Graphics by Davies Surya and Arvin Supriyadi in Jakarta.