How fraud is executed at agency

To pull off such a fraud, insiders say, one would require the involvement of several departments.

Some of these units are directly under the Commissioner of Customs office, notably the Document Processing Centre (DPC).

The ICT department is the main culprit, being the custodian of all the systems at the Kenya Revenue Authority (KRA).

Employees from this department have mostly been accused of manipulating the Simba system.

They are directly appointed by the Commissioner General and the Head of ICT, with insiders saying employees in this department are some of the most pampered.

Some can afford to buy a house in Nairobi within just months of employment.

The other department that is under scrutiny is the Finance Department. It is this unit that confirmed money had been received when no cash had been credited to KRA's accounts.

But it is the role of banks in the scam that is set to open the lid on just how deep the scam runs since it will need high level planning to execute it.

"Banks use suspense accounts to credit a given transaction where the money is immediately withdrawn once the goods have been released from the port," the source familiar with the investigations said. To be able to penetrate the system, one has to have a bird's eye view of the entire KRA operations from the time the goods arrive at the port to the time they are released into the market.