National Police Commissioner Jackie Selebi was ordered by the magistrate to return to the court on June 26, when he is expected to face charges of corruption, fraud, money laundering and racketeering. It was his first appearance in the case.

The police chief is among a number of high-profile officials ensnared in corruption investigations, which have drawn accusations of high-level political manipulation and stoked investor worries about political instability.

The case stems from Selebi's relationship with Glenn Agliotti, a convicted drug smuggler accused of playing a role in the 2005 murder of a South African mining magnate. Prosecutors accuse Selebi of receiving payments from Agliotti.

A spokesman for South Africa's National Prosecuting Authority said it was possible that Selebi, who is a political ally of President Thabo Mbeki and was president of Interpol until he resigned last month, could face additional charges.

"It is a possibility," NPA spokesman Tlali Tlali said outside the court after the hour-long hearing, which occurred amid tight security.

The formal warning from the magistrate means Selebi has to return, but he does not have to pay bail. Selebi failed in earlier efforts to get courts to stop the investigation.

Selebi, who has been placed on extended leave by Mbeki, appeared relaxed and joked with reporters at the court. He showed up voluntarily as part of an agreement with prosecutors, who promised not to arrest him.

Among other top officials caught in corruption investigations is Jacob Zuma, the new leader of the ruling African National Congress. He is due to go on trial in August on separate corruption-related charges.

The cases have prompted accusations from Zuma supporters and Selebi critics that Mbeki and his senior aides have intervened in the justice system for political reasons.

Zuma was charged with corruption, fraud, money laundering and racketeering shortly after defeating Mbeki for the ANC leadership in December. The case against Selebi was stalled for months despite a warrant having been issued for his arrest.