It has been confirmed that the team of about ten experts from ABSA Group Limited, the NBC parent company, spent several days at the bank's headquarters in Dar es Salaam before leaving for home over the weekend.
ABSA Group owns 55 per cent of the shares in NBC, one of the country's biggest commercial banks.
Other shareholders are the (Tanzanian) government (30 per cent) and the International Finance Corporation (15 per cent).
The ABSA team from South Africa is understood to have investigated allegations of massive fraud at the bank, which has recently been hit by a series of internal thefts involving billions of shillings.
Well-informed banking sector sources told THISDAY: "The fraud experts went through the various NBC departments, particularly the credit section, as part of their mission."
"They stayed at the bank for four or five days, during which they perused dozens of files and bank transactions deemed suspicious."
It is understood that the team will now compile a report for the ABSA Group top hierarchy, which will probably include recommendations for personnel, institutional, and operational changes to be implemented within NBC in the wake of the scandal.
"They were working closely with local NBC staff members to try to establish how it all went down and who precisely were involved in the massive fraud," the sources said, adding that investigators from the Prevention and Combating of Corruption Bureau (PCCB) were also involved in the probe.
At least four junior staff members at NBC have already been removed from their posts as a result of the investigation. But officials say some of the more senior bank officials implicated in the fraud are still clinging to their jobs, hence raising fears that they may end up tampering with whatever evidence there is.
Said the source: “The lower-ranking officials already fired by the bank were just used as scapegoats in the whole scam. All the more senior officials have remained untouched so far."
According to PCCB officials, the Bureau is conducting its own major investigation into a fresh series of fraud incidents and financial crime within local banks and financial institutions, with NBC cited as one of the banks hardest hit by the wave.
According to THISDAY findings, some senior personnel in many of these banks and financial institutions are being probed on suspicion of conspiring with expert fraudsters to siphon away billions of shillings.
PCCB director general Dr Edward Hoseah has said preliminary investigations show the problem to be much bigger and complex than initially thought.