Health Minister Manto Tshabalala-Msimang not only instructed the Medical Research Council (MRC) to find out who leaked its report into Aids mortality - she also named the suspected culprit.

In a scathing attack on the MRC's president, Malegapuru William Makgoba, she says she "would like to highlight the fact that this is not the first time that the MRC president has acted against government".

"You will recall that when the president of South Africa established a website for the members of the Presidential Advisory Council on Aids to debate their different points of view, the MRC president was instrumental in establishing a separate website for the orthodox scientists, under the umbrella of the MRC."

Tshabalala-Msimang's statements are made in an angry letter, dated September 17 last year, to MRC board chairperson Taole Mokoena - whom she appointed.

In the letter, she demands that "corrective action" be taken in the wake of the leaking of the MRC's report into mortality.

The report said that by 2000, Aids was the leading cause of death in South Africa. This contradicted statements by President Thabo Mbeki that crime accounts for most deaths.

The letter accuses Makgoba of being the source of the leak - but the investigation has cleared him and three other senior MRC staff members.

"The (health department) director-general (Ayanda Ntsaluba) advised the MRC president and his team not to release the report until the report had been presented to the minister of health and the cabinet," Tshabalala-Msimang wrote.

Last month, the Cape Times's sister paper, The Star, reported that after the MRC had "received an angry letter" from Tshabalala-Msimang demanding an official inquiry, the council paid a private consultancy, Triumvirate, to find out who had leaked the report.

In response, the health department attacked The Star, saying: "If there was ever a letter written by the minister to the MRC suggesting an investigation, let The Star and other Independent newspapers that carried the story publish (it)."

On Wednesdy Mokoena announced the outcome of the investigation into the leak: the identity of the person who leaked the report remained a mystery. "It should be made clear that the board was not at any time asked by anybody, neither the minister nor officials from the department of health, to instigate the investigation."

But, in spite of Mokoena's protestations, the minister's letter instructed the MRC board to: "Address themselves to the contents of this letter... and to inform me about the corrective actions they intend taking."

While releasing the investigation results on Wednesday, Mokoena insisted: "We don't take instructions from anyone. The act of the MRC instructs us to research those policy areas that are important to government and to the nation."

On Wednesday Tshabalala-Msimang's spokesperson, Sibani Mngadi, continued to deny that the MRC had acted on the minister's instructions and said the findings were of "no relevance" to his department.

"I am just happy that now South Africans will know that it was the MRC who commissioned its own investigation and it was not instructed to do so by the department of health," he said.

After the press conference, he sent a quick SMS message to The Star: "Hope you will have courtesy to apologise about MRC investigation."