Yak Yew Chee has been imprisoned for 18 weeks and fined over $16,000.

Singapore's State Court has jailed a former private banker and senior vice president for BSI Singapore for 18 weeks after he was found guilty of forgery and failure to disclose suspicious transactions.

Yak Yew Chee handled BSI's relationship with Malaysia's state-owned investment fund 1MDB, which is currently the subject of money laundering investigations in at least six countries, including Switzerland, Singapore and the US.

Chee pleaded guilty to four of seven charges and has also been fined S$24,000 ($16,949), according to reports published by Reuters.

Two charges against him related to forging reference letters for Malaysian businessman Low Taek Jho, who was described by Singaporean authorities as a “key figure” in the money laundering investigation into 1MDB, and for whom Chee worked as a private banker.

Another two charges related to turning a blind eye to hefty sums of money that were allegedly obtained illicitly and which coursed through BSI Singapore.

Chee is now expected to assist in the ongoing 1MDB money laundering investigation, Reuters reported.

Court documents revealed that Chee earned S$27 million throughout a four-year period of working for BSI.

Earlier this year, BSI and Falcon Private Bank were both shut down in Singapore amid the country's biggest crackdown on alleged money laundering connected to 1MDB.

The Malaysian prime minister, Najib Razak, has denied any wrongdoing and said Malaysia will cooperate with international investigations. 

BSI declined to comment when contacted by this publication.