The 86-year-old Catholic was gagged and bound with typewriter cord at the Sacred Heart Home in Ixopo, before being raped by multiple intruders.
Sister Gertrud Tiefenbacher was alone in her room when she was set upon by the men, who took a small amount of cash from the property after killing her.
The South African community has reacted with shock at the incident, and a large scale manhunt has been started to find the perpetrators.
‘She had a very kind heart and was loved by everyone’ said her friend and fellow nun Sister Gerald.
Another friend, Betty Firmstone, 85, said: ‘I met sister in 1952, when I started teaching at a school attached to the mission. We worked very closely together. She loved her work with children.’
‘This really was an act of savagery against a gentle, caring soul.’
The nun had moved to South Africa from Austria and was well loved by the religious community.