Police were called to their address on Saturday morning at around 09h00 by a family member who had reportedly found their bodies. The elderly couple, who were declared dead on the scene, had been tied up.
Graeme’s brother, Lance Bloch, said: "Our mother Rosalie Bloch and her common-law husband of about 30 years, Aubrey Jackson. I’m still numb and shocked."
Rosalie was a popular anti-apartheid activist who was seen just 10 days ago at a Black Sash event.
Michael Weeder, the Dean of St George’s Cathedral in Cape Town, said "the tragic, awful manner" in which the couple’s lives were ended "is sad beyond words".
He said Rosalie will always be remembered for the "shelter and hospitality she extended to those on the run in our dark days. The support she gave to the families of detainees.
"Our love and prayers to Graeme Bloch and his wife Cheryl Carolus and to Lance and all other members of the family.
"I pray that the family will take comfort from the way their loved ones feasted on the goodness of the perennial struggle for justice."