SINGAPORE — Singapore authorities have, for the first time, named Malaysian tycoon Low Taek Jho as a “key person of interest” in their investigations into the most high-profile money-laundering case here.

The disclosure came from Commercial Affairs Department (CAD) investigation officer Oh Yong Yang, who was testifying on the eighth day of the trial of ex-BSI banker Yeo Jiawei.

Mr Oh told the court yesterday that Mr Low and his business associates Eric Tan Kim Loong and Mohamed Badawy Al Husseiny are persons of interest in their investigations into a money-laundering case involving billions of dollars in transactions.

Investigations on Mr Low, also known as Jho Low, began in 2015 and he is also a person of interest in related investigations in other jurisdictions, Mr Oh said.

Mr Low, a Malaysian financier, is suspected of siphoning billions of dollars from Malaysia state fund 1Malaysia Development Berhad (1MDB). He has been linked to Malaysian Prime Minister Najib Razak and reports have earlier claimed that he had orchestrated a 2009 joint venture between 1MDB and PetroSaudi International to allegedly siphon off US$700 million (S$985 million).

In July, the United States Department of Justice filed lawsuits that sought to seize dozens of properties linked to 1MDB and had named Mr Low as one of those involved in the case.

The other key persons of interests in the Singapore investigations include Mr Tan, a Malaysian associate of Mr Low. Mr Tan is allegedly the stated beneficial owner of several bank accounts into which misappropriated 1MDB funds were transferred.

Mr Low’s other business associate, Mr Al Husseiny, is the former chairman of Falcon Bank and former chief executive officer of Aabar Investments PJS, a sovereign wealth fund based in Abu Dhabi.

In launching his defence yesterday, Yeo, 33, claimed to have played a backseat role in the multi-million deals that have come under scrutiny, and is not close to his former colleagues and other associates.

He is facing trial for perverting the course of justice by allegedly interfering with witnesses central to investigations. He also faces another seven charges of cheating, forgery and money-laundering, which will be dealt with in April next year.

Yeo told the court that his role in the bank was that of a support staff member for the private bankers and mostly took instructions from his direct supervisor, BSI’s former director of wealth management services Kevin Michael Swampillai. Yeo worked at the bank between 2009 and 2014.

For instance, while working the deal with 1MDB-owned Brazen Sky, he said that he was “never the one negotiating” and did what his supervisor instructed him to do.

BSI had entered into an agreement with fund management company Bridge Partners International Management in 2012, which involved US$2.3 billion from Brazen Sky. Former BSI banker Yak Yew Chee had brokered this deal.

Mr Swampillai, the prosecution’s witness, had helped negotiate the deal while Yeo is suspected to have a hand in it. The pair are said to have pocketed about US$5 million through transactions into two companies they owned — Bridgerock Investment and GTB Investment.

Yak now faces charges of graft, forgery and failing to report information on suspicious transactions to the authorities, while Mr Swampillai was among the senior BSI employees that the Monetary Authority of Singapore referred to the police for investigations.

Yeo denied that he was friends with Mr Swampillai, describing him as quite demanding at times. He added that his career depended on Mr Swampillai, who determined whether to put Yeo up for promotion, among other things.

In court, Yeo also tried to distance himself from Mr Low. The prosecution’s witnesses had earlier testified that Yeo started working for Mr Low after he left BSI and lived the high life, such as flying in private jets.

Yeo claimed that while he was in BSI, he never received direct instructions from Mr Low and usually got them through Yak or Mr Swampillai.

The trial continues today.