JOHANNESBURG (AP) — The former South African state prosecutor who led the case against convicted murderer Oscar Pistorius is prepared to take legal action against Jacob Zuma, the ex-president who left office last week following a series of scandals.

A group called AfriForum said Sunday that Gerrie Nel, head of the group's private prosecuting unit, will go to court if state prosecutors decide not to bring charges against Zuma for alleged corruption in an arms deal in the 1990s, when he was deputy president. Zuma has denied wrongdoing.

Nel was known for his sharp questioning of witnesses during the trial of Pistorius, who is serving a 15-year jail sentence for murdering girlfriend Reeva Steenkamp.

Nel quit the National Prosecuting Authority last year and joined AfriForum, which primarily represents South Africa's white Afrikaner minority.