Marike de Klerk, ex-wife of former South African president FW de Klerk, was stabbed and strangled to death in her home in Western Cape, police confirmed on Wednesday.
Police superintendent Wicus Holtzhausen said a post mortem was conducted after Marike was found dead by her hairdresser on Tuesday afternoon.
He said she had sustained a stab wound to the back and was then strangled.
Holtzhausen said nothing was missing from her house and the motive for the attack was not known. There were no signs of forced entry into her house.
The police officer said the Dolphin Beach complex, where Marike 's home is located, had 24 hour security and the units were not freestanding.
Meanwhile, tributes continued to pour in from across the political spectrum.
On Tuesday night President Thabo Mbeki's spokesman Bheki Khumalo said the president and his family learnt with "great shock of the untimely death of Marike de Klerk."
"She will be remembered by South Africans as a strong, charming and dignified woman," Khumalo quoted Mbeki as saying.
Winnie Madikizela-Mandela, president of African National Congress Women's League, said through her spokesman Alan Reynolds: "As a woman, I can identify with the exhaustion of her emotional resources in shaping her former husband's career."
The de Klerks divorced in 1998 after a marriage of 39 years, when he admitted to an affair with Elita Georgiades, wife of a Greek shipping tycoon.
The couple, married on April 11, 1959, have three children.
Mrs de Klerk was active throughout her former husband's political career in the National Party and led the party's women's organization.
The former president was in Sweden to celebrate the 100th anniversary of the Nobel Prize and was not available for comment.
He and former president Nelson Mandela jointly won the 1994 Nobel Peace Prize for ending apartheid.