1MDB-linked former banker Yeo JiaWei had amassed S$26 million (RM78 million) by the age of 32, according to Singapore's Straits Times.

This was told to a Singapore court where the former BSI Bank employee is on trial for four charges, including money laundering, forgery, cheating and attempting to pervert the course of justice.

Yeo's former supervisor Kevin Swampillai testified at the trial as a witness.

Swampillai admitted he too made S$6.95 million (RM21 million) in "secret profits" by "implementing various structures and undertaking financial arrangements" for a group of BSI clients.

He is now unemployed after being suspended by BSI Bank.

Swampillai testified how Yeo and him worked together with intermediaries to make such "secret profits"

He said among their source of secret commission was Bridge Partners International Management, where 1MDB's "fund units" were held.

Another source of commission, Swampillai said, was a fund called Devonshire.

According to the US Department of Justice, Devonshire Capital Growth Fund was one of three funds used to divert US$1.59 billion of 1MDB Global Investment Limited's money to Tanore Finance.

He also testified that Yeo left BSI Bank in 2014 to work for Malaysian tycoon Low Taek Jho, better known as Jho Low.

Swampillai said he continued to communicate with Yeo openly after the latter left BSI Bank but things changed when Singapore's Commercial Affairs Department (CAD) moved in on them.

"As things started to get tense with information coming out in the media in relation to these transactions and the CAD investigations began, communications were almost exclusively through Telegram and use of secondary phones," he was quoted as saying.

Yeo's trial will run until Nov 11. Two other former BSI bankers Yak Yew Chee and Yvonne Seah have also been charged with money laundering.