Malaysian Deputy Prime Minister Ahmad Zahid Hamidi has said the government is firmly committed to resolving issues regarding the civil lawsuits filed by the United States' Department of Justice (DOJ) in connection with a probe of state fund 1Malaysia Development Berhad (1MDB).

He said Malaysia welcomes the efforts by the DOJ in battling international corruption and urges all parties involved to cooperate fully.

Last Wednesday, the DOJ sought to seize US$1 billion (S$1.36 billion) in assets allegedly bought with money stolen from 1MDB. It said over US$3.5 billion was misappropriated from the fund.

Parti Islam SeMalaysia president Abdul Hadi Awang also weighed in on the 1MDB case yesterday, warning against foreigners meddling in Malaysia's affairs, said a report by Mingguan Malaysia newspaper.

He said that 1MDB should be probed by Malaysians rather than foreigners.

Meanwhile, rights campaigner and former Malaysian Bar Council president Datuk Ambiga Sreenevasan has blamed Prime Minister Najib Razak and his Cabinet for 1MDB's problems and said that they should resign.

Here is a quick look at 1MDB's latest woes:

Q What is the 1MDB?

A It is an investment fund owned by the Malaysian Finance Ministry that took shape in 2009 under Datuk Seri Najib, who is also Finance Minister and who led the fund's advisory board until May this year.

The fund started off as the Terengganu Investment Authority but was developed into its present form with the help of businessman Low Taek Jho, better known as Jho Low.

1MDB raised billions of dollars through bond issues for use in its investment projects.

The fund in its early days said it invested in petroleum assets and bought power plants in several countries. But it borrowed heavily and soon racked up debts of some RM42 billion (S$14 billion).

It has been paring down its debt burden by various means, including selling its power plants to a China company.

But it faces a bigger, politically explosive problem - billions in missing funds.

Q What about the missing money?

A Apart from debt issues, 1MDB faces a series of probes on large sums of money that appear to have been siphoned off illegally via a global network of shell companies.

Countries such as the United States, Switzerland and Singapore are also drawn into the investigations because of the movement of money through the international banking system.

Swiss investigators estimate that about US$4 billion has vanished from 1MDB's coffers.

Separately, Malaysia's parliamentary Public Accounts Committee (PAC) concluded in April after its probe that some US$3.5 billion had disappeared into a company based in the British Virgin Islands that has since been closed.

The DOJ's civil suit to seize over US$1 billion in assets is eye-opening for the large sums involved, the names highlighted and the connections made in the money trail.

US officials also noted the contrast between 1MDB's mission of national development and the lavish spending on luxury residential properties, pricey works of art and gambling binges by the small group of people named in its lawsuit. The aim is to force the forfeiture of their ill-gotten assets.

In an ironic twist, some of the funds were said to have gone into the making of the Hollywood movie The Wolf Of Wall Street, which featured Leonardo DiCaprio in the role of a stockbroker convicted of fraud. The film production company insists its source of funding is legitimate.

Q Why is this 1MDB money problem a political issue?

A The DOJ's filing named as beneficiaries of this money Mr Riza Aziz, the stepson of Mr Najib, and Mr Low, a close friend of Mr Riza.

An unnamed "Malaysian Official 1" was also said to have received millions diverted from the fund.

US Attorney-General Loretta Lynch has declined to address speculation that Mr Najib was that recipient.

Q Why are foreign countries like the US involved in the 1MDB probes?

A Foreign countries are involved as big sums of money of questionable origins were detected flowing through their financial systems.

An ally of ex-premier Tun Dr Mahathir Mohamad had also gone to some of these countries to lodge complaints related to the missing funds.

As Ms Lynch explained at a press conference last Wednesday: "The Department of Justice will not allow the American financial system to be used as a conduit for corruption."

She added: "Corrupt officials around the world should make no mistake that we will be relentless in our efforts to deny them the proceeds of their crimes."

Singapore, too, has said it will not tolerate abuse of its banking system by the corrupt.

Q What is the US Kleptocracy Asset Recovery Initiative?

A It is a unit within the DOJ set up six years ago to identify and seize assets held by corrupt foreign leaders and their cronies in the US. The 1MDB case is its biggest so far.

Q What is the Malaysia government's response?

A Mr Najib has denied any wrongdoing in the case.

"We have to establish the facts first. This is a civil action, this is not a criminal action. It is limited to the names mentioned in the DOJ report," he said in response to media queries last Thursday.

Mr Najib said that those named in the suits, including his stepson Mr Riza, have the right to legal process in the US.

The government said it will cooperate with lawful investigations of local companies or its citizens.

Malaysian Anti-Corruption Commission (MACC) Chief Commissioner Abu Kassim Mohamed confirmed yesterday that the agency is cooperating with the US Federal Bureau of Investigation (FBI) on the 1MDB probe.

Tan Sri Abu Kassim said the MACC is investigating a businessman who is said to have cheated 1MDB, and who was involved in laundering money before taking it to the US, according to Bernama news agency.

"The US sought our assistance and we only assisted as provided under the United Nations' Convention Against Corruption. (Under the convention), agencies are required to give their cooperation and support when confronted with a crime involving several countries," he said.