January 2009: The Malaysian government launches 1 Malaysia Development Berhad (1MDB), a state-owned company aimed at encouraging foreign direct investment. Its chairman is deputy prime minister Najib Razak.

April 2009: Mr Najib becomes prime minister of Malaysia and continues his role with 1MDB.

September 2009: 1MDB signs its first major deal, a joint venture with Saudi oil firm PetroSaudi. A draft report by Malaysia's auditor-general indicates that of $US1 billion invested from 1MDB, approximately $US700 million instead moves to another company's bank account. That company, Good Star, was set up by a young Malaysian financier called Low Taek Jho, or Jho Low.

May 2010: 1MDB signs deals with sovereign wealth funds in the Gulf emirates of Qatar and Abu Dhabi. Prime land in Kuala Lumpur is sold to 1MDB at below-market rates to develop a financial centre, in a joint venture with Abu Dhabi's state-owned Mubadala Development Company. After spending nearly $US2 million on a launch party, 1MDB ditches the event when Abu Dhabi's crown prince decides not to attend.

May 2014: The Sarawak Report, a whistleblowing website run by British investigative journalist Clare Rewcastle Brown, begins to publish allegations about misappropriation of state funds by 1MDB.

July 2015: Malaysia ignores an Australian request for assistance in a case involving allegations of bribery by two Australian Reserve Bank firms over contracts to print bank notes. People who had worked in the office of Mr Najib are implicated but DFAT obtains a suppression order to prevent his name being linked to the case. The whistleblowing website WikiLeaks publishes the suppression order, forcing Victoria's Supreme Court to revoke it.

Malaysia's deputy prime minister Muhyiddin Yassin publicly calls for Mr Najib to offer an explanation of the 1MDB scandal. He and four other ministers are promptly sacked, and Malaysian attorney-general Abdul Gani Patail is replaced with Mohamed Apandi Ali, a party ally of Mr Najib's.

August 2015: The streets of Kuala Lumpur are filled with protesters demanding Mr Najib's resignation over the scandal. In an address to party faithful Mr Najib warns "white people" to stay out of Malaysia's affairs - widely seen as a reference to Clare Rewcastle Brown. Malaysia applies for an Interpol "red notice" to have her arrested and extradited. Interpol tells police forces to ignore the application.

January 2016: Despite continuing allegations that 1MDB is being used by Mr Najib as a personal and political slush fund, Attorney-General Mohamed Apandi Ali announces that a sum of $US681 million which reportedly flowed to Mr Najib's account through an anonymous British Virgin Islands company and a Swiss private account owned by an Abu Dhabi sovereign wealth fund was a "personal donation" from the Saudi royal family. He says that $US620 million of the sum was returned unspent, there was no criminal offence and the matter is now closed. This prompts the Saudis to announce their own investigation.

February 2016: The New York Times quotes a member of the Saudi royal family and an associate of the royal family as saying that the money came from a Saudi prince - but that it was not a donation. The Swiss attorney-general's office says its investigators have found evidence suggesting that $US4 billion had been misappropriated from Malaysian state-owned companies.

March 2016: Mr Najib tells a political rally in the Malaysian city of Kuantan that people shouldn't "think I am a crook".

April 2016: 1MDB denies that it had provided funds to finance the 2013 Hollywood film The Wolf of Wall Street.

May 2016: Authorities in Switzerland and Singapore open criminal proceedings against Swiss private bank BSI SA for allegedly failing to prevent suspected money laundering and bribery related to its dealings with 1MDB.

July 2016: US prosecutors sue to seize more than $US1 billion in assets they say are tied to an international scheme to launder money stolen from 1MDB, used to finance The Wolf of Wall Street and to buy property and famous works of art. Mr Najib is not named in the suit, which refers instead to "Malaysian Official 1", however his stepson Riza Aziz is named, as are Jho Low and Abu Dhabi government officials Khadem Abdulla al-Qubaisi and Mohammed Ahmed Badawy al-Husseiny. It is the largest set of cases ever brought by the US Justice Department's Kleptocracy Asset Recovery Initiative.

Fairfax Media