South African Minister of Justice Jimmy Kruger faces a "deeply concerned" Cabinet Tuesday on the mystery surrounding the death of black leader Steve Biko amid growing demands - particular from whites - that Kruger resign.

The increasing rage was evidenced today at a rally organized by the opposition Progressive Federal Party at Johannesburg city hall, where almost 2,000 people - most of then white - "passed a resolution" calling for Kruger's resignation repeal of laws allowing detention without trial, and an independent inquiry into all 21 of the deaths in detention over the past 18 months.

Kowie Marais, a prominent former judge and once a member of the ruling National Party, told the crowd that Bikos death in detention last week had turned him into a "complete and unequivocal enemy of the security legislation in South Africa." The moving statement from an Afrikaner and a once-staunch supporter of the government indicated the depth of the impact of Biko's death.

To applause and cheers of approval, Marais said tha Kruger has no right to hide behind senior policemen and that bungling over the Biko case indicated that it is time for the minister to be removed.

The government hierachy, including Prime Minister John Vorster, is reported to be gravely upset about the handling of the case and its repercussions abroad. One source said, "Kruger's neck is on the line over this one. It's not just the opposition that's raising hell."

While the case is likely to get its first airing in Tuesday's Cabinet session, government sources say this will be only the first of several sessions. As one source acknowledged, the jury is no longer just opponents of the government, but the entire country and much of the Western world. "I guess the government's first mistake was to underestimae how important Steve Biko really was, and it all enowballed from there," he said.

An editorial in the pro-government newspaper Rapport added its voice to the demand for a general investigation into the recent deaths in detention.

"It no longer the security police's reputation that is at stake, but that of South Africa," the editorial warned. "One can only shake one's head over the handling of the matter. Already, only only days after his death, there have been so many contradictory statements that it has caused concern rather than alleviated it."

The minister's office said today that Kruger would have no further comment on the controversy until the final postmortem results are ready.

Even the timing on the autopsy has grown into a dispute. A Johannesburg pathologist said today that a normal autopsy would take only three days, whereas the government pathologists has already taken a week and said the final results may not be known for as long as a month. Chief government pathologist J. L. Loubser explained that certain tests involve lengthy processes because body tissues are left in fixatives before examination.

But neither the government pathologist nor the Biko family pathologist, Jonathan Gluckman, was willing to confirm or deny reports that the preliminary post-mortem indicated that Biko suffered multiple brain and body injuries before his death.

Gluckman said only: "I am confident that no source close to tha autopsy would have made such a statement. The job is not completed until the microscopic-chemical work is completed."

Gluckman also declined to comment on the statement from Editor Donal Woods, a Biko family friend, made after he saw Biko's body Saturday night, Woods said. "There appears to be a pronounced swelling on Steve's forehead, and Ntsiki [Biko's widow] and I noted a distortion of his features.But to what extent these and other effects are due to the post-mortem operation will no doubt emerge at the inquest."

Loubser commented today, in evidential matters of this kind I will not confirm and I will not deny that Mr. Biko's body was found at the post-mortem to have brain or rib injuries."

Rib injuries were never specifically mentioned in the original report on Biko's injuries. Although rib injuries were one of the possible body injuries originally indicated in private to me.

Another speaker at the mass rally, Helen Suzman, progressive Federal member of Parliament, charged Kruger with "gross callousness" in handing the case and said South African security laws were actually behind the death of one of South Africa's most prominent blacks.

She blasted the government for depriving citizens of their "civil liberties and the normal protection of the rule of law enjoyed by citizens in all Western countries."