Goldman Sachs had disclosed to regulators last month that the letter its Southeast Asia chairman wrote in favour of the man widely believed to be at or near the centre of the entire 1MDB saga contained what it called “inaccurate” information.

The letter, written to another bank, suggested that Goldman Sachs had vetted Low and had done business directly with him.

In actual fact the bank had not subjected Low to sufficient due diligence to be able to vouch for him, Bloomberg claimed, citing an unnamed source.

Goldman Sachs and Leissner are reported to be presently in a dispute over restricted stock and options he earned during his last year of service.

However, that deadlock, if unresolved, may put the investment bank in difficulties.

Although neither the bank nor Leissner are subject to an on-going FBI probe said to be looking into 1MDB funds, Leissner himself has been subpoenaed to testify before a grand jury later this month.

If the deadlock continues, investigators probing the matter may deduce that Goldman Sachs still has some leverage over Leissner which may in turn raise issues of bias affecting his testimony, law professor and former federal prosecutor Samuel Buell was reported to have suggested.

It would then fall upon the bank to explain itself, New York lawyer Michael Bowe was quoted as saying.

One possible explanation would be that the bank’s actions were in line with recent calls by regulators to freeze or cancel the pay of employees who violate established rules and policies governing the industry.