The office of Nigeria’s Attorney General said on Tuesday that a whistleblower prompted an investigation into alleged MTN infractions that last week led to a demand for $8.1 billion taken out of Nigeria to be brought back.

Ladidi Mohammed, head of asset recovery, told Reuters in a phone interview that an investigation was then carried out by the Central Bank of Nigeria, CBN.

The South African telecoms giant in a statement issued on Tuesday said all dividend repatriation out of Nigeria was done on the basis of equity capital and with valid certificates.

Meanwhile, MTN has landed into another bout of trouble with Nigeria’s federal authorities. This time round, the largest telecom operator in the country is alleged to owing $2 billion in taxes.

Nigeria has piled up pressure on the corrupt using the whistle blower policy which has led to bursting several financial heists.