1MDB, whose advisory board is chaired by Prime Minister Najib Abdul Razak, is being examined by Malaysian authorities investigating accusations of financial mismanagement and graft.
The fund has been dogged by controversy over its US$11 billion debt and alleged financial mismanagement.
"The Office of the Attorney-General confirms that, on Aug 14 2015, it opened a criminal procedure against two entities of 1MDB as well as against an unknown person," the OAG spokesperson said in an email.
The case involved "suspected corruption of public foreign officials, dishonest management of public interests and money laundering", he said.
The criminal proceedings follow two communications from the Money Laundering Reporting Office Switzerland (MROS) the spokesperson added.
News of the investigation was first reported by Swiss newspaperLe Temps.
Swiss financial regulator FINMA said on Wednesday it was checking with some of the country's banks whether they carried out business with 1MDB, according to Reuters.
BMF: Probe may be links to dealiing with PSI
Meanwhile, Swiss-based NGO Bruno Manser Fund (BMF) which had lodged complaints about 1MDB in its home country said the probe may be linked to 1MDB’s dealing with PetroSaudi International.




Citing an email communication, BMF said the probe is being conducted under article 305bis (money laundering), article 314 (misconduct in public office) and article 322 septies (bribery of foreign public officials) of the Swiss criminal code.
“The OAG said the criminal proceedings were based on two reports by the Money-Laundering Reporting Office Switzerland.
“The BMF urges the Swiss authorities to extend the criminal proceedings against several banks involved in the 1MDB money-laundering operation, namely Coutts, JP Morgan, Falcon Private Bank and BSI,” it said in a statement today.
On Thursday, former Batu Kawan Umno vice chief Khairuddin Abu Hassan revealed that he had submitted evidence to the Swiss attorney-general.
Khairuddin was sacked from his Umno post and was subsequently declared bankrupt with a money-laundering probe brought against him after he began attacking Prime Minister Najib Abdul Razak on 1MDB.
Khairuddin was accompanied by lawyer Matthias Chang, a former aide of ex-premier Dr Mahathir Mohamad, when submitting the evidence to Swiss authorities.
Malaysiakini