Afriforum says approximately $48 million was laundered from the Bank of Botswana via international accounts and distributed to banks in South Africa.
According to the organisation, the money-laundering case involves high-profile politicians in South Africa, including Bridgette Motsepe-Radebe.
Advocate Gerrie Nel, who leads the organisation's private prosecution unit, was appointed officially by the Botswana government and its director of public prosecutions (DPP), Stephen Tiroyakgosi to represent South Africa and assist in the case on Tuesday along with advocate Phyllis Vorster of Afriforum.
During a media briefing, Nel said the brief on the case from the DPP was to facilitate developments relating to a request for mutual legal assistance in the Bank of Botswana case.
"This particular request was personally handed over to the head of the international cooperation unit in Mr Tiroyakgosi's office to the designated officials at the department of international relations and cooperation (Dirco) on 19 September 2019, but this request has since disappeared for convenience," he said.
Nel said the DPP was denied to access to accounts by banks in South Africa to seek information for the investigation despite obtaining a court order.
"During a bail application by the accused in this matter, the South African banks agreed to furnish letters to an individual without a warrant, that indicated certain accounts didn't exist. The banks didn't assist law enforcement in Botswana, but issued letters to this individual which will also be investigated.
"The fact that Dirco failed to give any feedback to the DPP of Bostwana over nine months indicates that the South Africa government is unwilling to assist our client with their request," he added.
The advocate further said the DPP had engaged with the department of justice and officials of the National Prosecuting Authority (NPA), but failed to receive feedback over its application to investigate.
"The justice department and NPA simply told us that they haven't received the application to deal with. South African authorities are obligated to respond to the request for mutual legal assistance which will the investigation moving forward," he said.
In 2019, Motsepe-Radebe had been accused of being a signatory on bank accounts valued at more than $10 billion, said to be stolen from the Botswana government, allegedly to finance a coup.
However, she maintained her innocence saying the accusations have been part of a smear campaign by the Botswana government, and once again called on authorities in Botswana and South Africa to investigate.
South African banks including Nedbank, Absa and Standard Bank had confirmed that Motsepe-Radebe was not a signatory on bank accounts set up for the alleged illicit money flows.
It was reported that she had also been imprisoned in Zimbabwe after a meeting with US diplomat Andrew Young and Khama. A tip-off claimed that she was smuggling money into the country to be used to buy votes for an opposition candidate in the Botswana election, Pelonomi Venson-Moitoi.
Motsepe-Radebe said the meeting was simply a diplomatic one, but that a publication had reported false information about it and also said she intended to sue the publication.
"I've never given money for anything regarding regime change, ever in my life, and if they say I have, then they have to prove it," she said.
She also faced allegations of an alleged affair with Botswana's former president, Ian Khama which she rebutted, saying she and Khama were just family friends.
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