S. Africa Slaying Blamed on Right-Wing Conspiracy : Assassination: Five whites are detained in Chris Hani’s murder. Police also investigate possibility international groups were involved.

Four white men and a white woman were detained before dawn Wednesday for questioning in the assassination of African National Congress leader Chris Hani, and police said they now are convinced that the killing was part of a right-wing white conspiracy.

“We believe there has been a conspiracy,” said Brigadier Frans Malherbe, a police spokesman.

He added that police also are investigating the possibility that international right-wing groups, which help fund South African extremists, were involved.

The latest arrests, the government acknowledgment of a conspiracy and the arrival this week of two European police experts to monitor the investigation has set up the most serious confrontation between President Frederik W. de Klerk and his right-wing opponents since he took office in 1989.

But the case also is the toughest test yet for De Klerk’s national police force, which lacks credibility among the country’s black majority and has been sharply criticized by ANC President Nelson Mandela for treating right-wing terrorists with “kid gloves.”

Responding to Mandela’s criticism, De Klerk told Parliament on Tuesday that he will not consider granting political amnesty to Hani’s killer under any circumstances.

Many on the right have applauded the assassination of Hani, a key ANC negotiator and also head of the South African Communist Party. Several extremist groups have offered to pay legal expenses for those charged.

Since Hani’s assassination April 10, the right has been blamed for at least two deaths of black protesters. And black fury over Hani’s death has resulted in sporadic looting and rioting. Now many South Africans fear the beginnings of a race war between left-wing blacks and right-wing whites.

Two of the five whites arrested early Wednesday were questioned and released later in the day, police said.

The three kept in custody were Gaye Derby-Lewis, a journalist with the Conservative Party newspaper Die Patriot (The Patriot); Arthur Kemp, who until January worked for the Citizen, a pro-government newspaper and the country’s largest-circulation daily, and Faan Venter, a real estate agent with right-wing links.

The trio joins two other white suspects. Janusz Walus, 40, a member of the right-wing Afrikaner Resistance Movement, was detained minutes after the assassination with the murder weapon in his car. A search of Walus’ home uncovered a hit list, containing the names and addresses of Hani, Mandela, other political leaders and journalists.

Police interrogations of Walus led to the arrest last weekend of Gaye Derby-Lewis’ 57-year-old husband, Clive, a Conservative Party leader and opposition member of De Klerk’s President’s Council.

The investigation of the murder itself has been completed, Malherbe said Wednesday, and the 17 officers assigned to the case now are looking into the alleged conspiracy. Malherbe said more arrests are expected, and he added that the ANC is being kept informed of progress in the investigation.

Acknowledgment of a conspiracy in Hani’s death marked a significant turnaround for the police. Only two hours after the assassination, De Klerk’s deputy minister of law and order said there was no evidence of a conspiracy. He was sharply criticized by ANC leaders for his hasty conclusion, and some anti-apartheid leaders feared a police cover-up.

In an attempt to head off ANC criticism, the government has agreed to invite two experts, approved by the ANC, to assist in the investigation.

Commander George Churchill-Coleman, former head of Scotland Yard’s anti-terrorist force, arrived here Wednesday and Dr. Ralf Kruger, a former judge, prosecutor and one of Germany’s top criminal investigators, is due Friday. Each man is accompanied by a small team of detectives.

“We have nothing to hide,” said Malherbe. “They will monitor the investigation and be in constant contact with the investigative team.”

The arrests of whites and the inclusion of foreign detectives in the investigation has drawn fire from the Conservative Party, which has accused De Klerk of trying to undermine his political opponents.

But Malherbe defended the arrests, saying the authorities will “not arrest somebody without rhyme or reason.”

“That is not our style,” he said. “We are investigating a criminal case and not the political affiliations of these people.”