KUALA LUMPUR (BLOOMBERG) - The Malaysian authorities have frozen about US$10 million (S$13.6 million) worth of assets as it investigates former Goldman Sachs Group banker Tim Leissner's claim that his once-lover blackmailed him over his role in the 1Malaysia Development Berhad (1MDB) scandal.

The Malaysian Anti-Corruption Commission (MACC) is probing the case under the Anti-Money Laundering Act, the agency's chief Azam Baki said at a press conference on Tuesday (March 1).

The same law was used to convict former prime minister Najib Razak for his involvement with 1MDB.

"We have called Rohana to record her statement and have taken steps to freeze related assets or cash," said Tan Sri Azam, referring to Ms Rohana Rozhan, the alleged former lover. "We will continue our efforts to investigate and return the related monies to our country."

Leissner, a star witness in the trial linked to Malaysian investment company 1MDB, told a United States court last week that he bought Ms Rozana a US$10 million house in London in 2013 after she threatened to expose his involvement in the fund.

Ms Rozana tendered her resignation as chief executive of Astro Malaysia in 2018, just a month before Najib was slapped with his first corruption charges in relation to 1MDB.

She said on Friday she was cooperating with officials and did not address the allegations in a two-line statement.

Azam said on Tuesday the MACC intended to summon more individuals for questioning, including those in the US.

This would require the help of the Attorney-General's Chambers, he said.

Meanwhile in the trial in New York, prosecutors said they want to conclude their questioning of Leissner on Tuesday by having him tell jurors how he met with Roger Ng and their wives in 2016 to concoct "a cover story", to conceal their fraud tied to the looting of 1MDB.

Leissner is the government's star witness against his former subordinate Ng, who is on trial accused of conspiring to bribe officials in Malaysia and Abu Dhabi from 1MDB bond deals.

The alleged mastermind of the scheme, fugitive financier Jho Low paid Leissner more than US$60 million in kickbacks while Ng got US$35 million, according to prosecutors.

Ng's lawyer Marc Agnifilo has argued the money Ng received was a transfer from an account controlled by Leissner's former wife Judy Chan to Ng's wife Hwee Bin Lim, for a legitimate separate business transaction between the two wives.

Prosecutors are attempting to persuade the judge to allow the testimony, even though Lim's statements occurred after the alleged conspiracy ended.

They are relevant and could refute Mr Agnifilo's claims the transfer of funds was legitimate, prosecutors said.

Mr Agnifilo did not immediately return an email seeking comment. He has said that Ms Lim will testify about the transaction as part of her husband's defence.

The US said Monday in a court filing that Leissner could describe a 2016 meeting he had with his former wife, Ng and Lim after questions were raised about the role Goldman bankers played in the 1MDB scandal in a series of published news articles.

Leissner could testify that after the couples met with a "feng shui master" in 2016, Ng's wife said "they needed to come up with a cover story to explain why Ms Chan had sent money" to an account controlled by her, according to the prosecutors.

Ng and his wife decided "the best story would be to say that the defendant had previously invested in Ms Chan's real estate business", prosecutors said Leissner would testify.

Leissner would also say that Ng and his wife "would fabricate a story" about the origins of the investment, according to the prosecutors. Prosecutors said that after Ng was arrested in Singapore in 2017, Ng's wife called Leissner "in a panic", Leissner would tell the jury.

Lim said they all needed to have "a common story" about the transfer of the money and said Ng had disclosed to investigators "nothing else about them", and "downplayed the current contact between" her husband and Leissner, according to the prosecutors.

Ng's trial, which is in its third week, was adjourned last Thursday afternoon until Tuesday to give Ng's lawyers time to review at least 15,500 documents belatedly provided by the US last week.