Geneva - Switzerland on Wednesday raised the pressure on Malaysia to co-operate with its probe into scandal-tainted 1MDB, saying new evidence indicated a "Ponzi scheme" was used to cover up US$800 million (S$1.10 billion) in misappropriations from the Malaysian state fund.
The Swiss attorney general's office opened an investigation into 1Malaysia Development Berhad (1MDB) in August 2015 following allegations that some of the billions of dollars that it alleges were stolen from 1MDB had passed through Swiss banks.
The Swiss attorney general initially asked for Kuala Lumpur's help in January, but that request was "still pending", said a statement from Switzerland's top prosecutor, Michael Lauber.
Lauber's office on Wednesday reissued its call for "mutual legal assistance from the Malaysian authorities", following a similar request earlier this year.
Citing new evidence in the 1MDB case, the attorney general's office (OAG) said it had "identified further suspect transactions involving the Swiss financial sector". A total of US$800 million purportedly invested in natural resources by the Malaysian company SRC, a former 1MDB subsidiary, "appears to have been misappropriated", the statement said.
The fraud "was committed based on a form of 'Ponzi' scheme", the OAG statement added.
A Ponzi scheme involves paying returns on investments with money from other investors, rather than from income generated by the investments themselves.
The OAG did not provide details of the alleged scheme.
Malaysia has been rocked for more than a year by allegations of a massive campaign of fraud and embezzlement surrounding 1MDB that is stunning in its scale and complexity.
The scandal has prompted calls for the ouster of Malaysian Prime Minister Najib Razak - who established 1MDB in 2009 - sparked a huge anti-Najib protest in the capital, and triggered investigations by authorities in several countries.
The US Justice Department filed lawsuits in the United States in July to recover billions in assets it said were purchased by Najib relatives and associates with money stolen from 1MDB.
The suits also said an unnamed Malaysian official as taking part in the theft. A spokesman for Najib's government has admitted that official was the prime minister, while denying he was a target of the US probe.
The US moved to seize assets including real estate in Beverly Hills, New York and London, artworks by Monet and Van Gogh, a Bombardier jet, and corporate ownership stakes.
A Najib spokesman did not immediately respond to a request for comment on the latest allegations, and no immediate comment was seen from Malaysia's attorney general, Mohamed Apandi Ali.
Apandi, who was appointed by Najib after the scandal broke, earlier this year cleared Najib of any wrongdoing, provoking outrage in Malaysia.
Najib has shut down domestic investigations. He and 1MDB deny any wrongdoing.
In January, Apandi promised to co-operate with the Swiss.
The OAG did not directly accuse Malaysian authorities for dragging their feet, but made clear that its initial request had not been answered.
"The OAG remains confident that the two requests for mutual legal assistance made to the authorities in Malaysia will be executed," the statement said.
In contrast, Swiss authorities noted their "full satisfaction" with co-operation from authorities in Singapore, through which some of the funds involved in the scandal moved.