Testify or Be Sent to Jail, Mandela Case Figures Told : South Africa: Pair still are silent but judge delays incarceration while police seek missing witness. State says it cannot proceed unless the men take stand.

A judge ordered two key state witnesses into custody Thursday for refusing to testify in the trial of Winnie Mandela, but he later postponed their incarceration for three weeks to give prosecutors time to find a crucial third witness.

The prosecution says it cannot proceed with its kidnaping and assault case against Mandela without the testimony of at least two of those three witnesses, all of whom have said that they were beaten by Winnie Mandela and others at her Soweto home in 1988.

The missing witness, Gabriel Mekgwe, was kidnaped Sunday night from a church home in Soweto, and his disappearance frightened the other two, Kenneth Kgase, 31, and Thabiso Mono, 21, who have now refused to testify. Police are looking for Mekgwe.

The attorney for Kgase and Mono had argued that his clients’ fears amounted to a “just excuse,” which, under South African law, means they should be allowed to refuse to testify.

Judge Michael S. Stegmann said he would “not make light of the fears expressed by the witnesses,” and he described the kidnaping of Mekgwe as the work “of a misguided and lawless person who intends to frustrate the ends of justice.”

The judge noted that the men’s fears center on their safety after the trial. They have rejected police protection during the trial but believe that testifying against Mrs. Mandela will “mark them permanently for reprisals,” the judge said.

However, Stegmann ruled that the men’s fears about the future are “too remote and speculative” to justify excusing them, and he ordered them to testify, promising to impose “an appropriate prison term” if they refuse. He is empowered by law to sentence them to up to five years in prison, and that term is renewable indefinitely until they agree to testify.

Despite the threat of imprisonment, the men still refused to testify Thursday. But they were saved from jail temporarily by prosecutor Jan Swanepoel, who, citing the men’s previous cooperation, asked the judge to withhold passing sentence and give the state time to search for Mekgwe. Both Kgase and Mono have said they would agree to testify if Mekgwe is found alive and well.

Stegmann agreed and postponed the case until March 6.

The case against Mrs. Mandela and three co-defendants has drawn wide attention in South Africa and raised fears that it could jeopardize negotiations between the government and the African National Congress.

Nelson Mandela, deputy president of the ANC, has been watching in the courtroom for most of the trial. In conversations with reporters, he has vigorously asserted his wife’s innocence, suggesting that the charges were part of a conspiracy by the state to discredit her.

So far, though, the case has not hampered relations between the ANC and the government. In fact, Nelson Mandela and President Frederik W. de Klerk met for important talks on Tuesday and agreed on a plan to resolve several problems in the peace process. Details of their agreement have not been released.

The case against Mrs. Mandela rests almost entirely on the testimony of Kgase, Mono and Mekgwe, who contend that they were abducted and taken to the Mandela home on Dec. 28, 1988, more than a year before Nelson Mandela’s release from years of imprisonment. The men testified in another trial last year that Mrs. Mandela had instigated the beatings of them and of 14-year-old Stompie Seipei, who was later found dead of stab wounds.

The state has been reluctant to force the men to testify, though, and its case has been weakened considerably by the week’s developments. If police do not find Mekgwe before the trial is resumed, prosecutors say, the government may be forced to drop the case.

Meanwhile, ANC leaders in Tumahole, Seipei’s hometown, contended Thursday that Seipei’s death was “being used by the media to harass our comrade Winnie Mandela, her husband and, ultimately, the ANC.”

Seipei’s mother, Mananki Seipei, who joined the ANC a few months ago, was presented by the leaders to bolster their claims. But, when asked what she thought of Winnie Mandela, Mrs. Seipei said: “I’m still not satisfied because she’s the ‘mother of the nation’ (and) I am expecting her . . . just to come to me and clear up these rumors” that she was involved in Seipei’s death.