(Adds comment from prosecutor)
SINGAPORE, July 12 (Reuters) - A Singapore court jailed a former wealth manager of Swiss bank BSI for four and a half years on Wednesday for money laundering and cheating in a case linked to investigations into the siphoning off of billions of dollars from Malaysian sovereign fund 1MDB.
A political storm has raged in Malaysia for the past two years over the scandal at 1Malaysia Development Berhad (1MDB), which is the focus of money laundering investigations in at least six countries, including Switzerland and the United States.
Singapore public prosecutor Nathaniel Khng described the Singapore investigation as "the most complex, sophisticated and largest money laundering case" ever carried out by the city-state's white collar police.
The former banker, Yeo Jiawei, 34, pleaded guilty to money laundering and cheating on Wednesday.
Yeo is already serving a 30-month term on charges of perverting the course of justice by urging witnesses to lie to police and destroy evidence during the investigation into illicitly transferred funds linked to 1MDB.
"The two schemes to secretly profit were dishonestly concealed from BSI Singapore ... and resulted in the accused earning in excess of US$3.5 million in illicit profits," the public prosecutor said.
Prosecutors also allege that Yeo played a central role in the illicit movement of S$23.9 million ($17.3 million) of 1MDB-linked funds both while he was working at the now defunct BSI Bank Singapore, and afterwards.
Prosecutor Khng said, however, that the central figure and one of the "key persons of interest" in investigations was Low Taek Jho, a Malaysian businessman who has dropped out of public view.
Low was an adviser to the state fund, whose advisory board had been chaired by Malaysian Prime Minister Najib Razak.
Najib has denied any wrongdoing in 1MDB's problems and said Malaysia would cooperate with the international investigations.
A U.S. Department of Justice investigation in June highlighted Low's role in the scandal.
The Singaporean prosecutor said the case against Yeo related to two transactions the objective of which appeared to have been to cover up the fact that $1 billion belonging to 1MDB had been transferred into a bank account that Low "beneficially owned".
Low's whereabouts are not known. Reuters sent an email to his Hong Kong-based company, Jynwel Capital, requesting comment from him. The company had not responded by Wednesday evening.
The prosecutor had called for a stiff sentence to be handed down to Yeo as a deterrent, partly in order to protect Singapores standing as an international financial centre.
Singapore's central bank announced in May that it has ended its review of banks with 1MDB-linked transactions.
As part of its two-year review, Singapore shut down the local units of BSI Bank and Falcon Bank due to failures of money laundering controls and improper conduct by senior management, froze millions of dollars in bank accounts and charged several private bankers.
A spokeswoman for EFG International, which now owns BSI bank, declined to comment.
Stefano Coduri, group chief executive of BSI bank stepped down after the closure of its Singapore operations last year and the bank said it had undertaken steps to strengthen management, including introducing a new chief risk officer and appointing a new group legal counsel.
Two other former BSI staffers have been convicted and sentenced on charges stemming from the money-laundering investigation linked to 1MDB. ($1 = 1.3799 Singapore dollars) (Reporting by Fathin Ungku; Additional reporting by Joshua O. Franklin in Zurich; Editing by Simon Cameron-Moore, Robert Birsel)