Duduzane Zuma, the son of former South African president Jacob Zuma, was released on bail after appearing in court in leg-irons on Monday on charges of corruption.
The National Prosecuting Authority's (NPA) spokesman Luvuyo Mfaku said the raid was part of an investigation into theft, fraud and money laundering at a state-backed dairy project in the Free State province.
Former South African president Jacob Zuma is to face corruption charges over a $2.5 billion arms deal, prosecutors said, as a years-old scandal returned to haunt him within weeks of his fall from power.
South African police raided the family home of businessmen friends of President Jacob Zuma on Wednesday amid a probe into allegations that the family used their links with the president to win state contracts and influence Cabinet appointments.
South African lender FirstRand said on Monday suspicions of money-laundering lay behind its decision to cut ties with a business family linked to allegations of influence-peddling in President Jacob Zuma's government.
President Jacob Zuma flouted the constitution in using public funds to upgrade his private residence and must repay the money, South Africa's top court ruled, sparking calls for his impeachment.
More senior South African public figures came out on Friday to accuse a business family with close ties to President Jacob Zuma of exerting undue influence, as top ANC officials met to discuss the political crisis.