Sipho Oupa Kubeka, 38, admitted that he had raped and strangled his grandmother, Konzaphi Elizabeth Kubeka, at her home near Buhlebuzile in KwaMhlanga in September last year.

The elderly woman was found dead in her bedroom. A post-mortem showed she had been sexually assaulted and had died of strangulation.

Kubeka testified he had a good relationship with his grandmother and had at times stayed with her.

When Judge Selby Baqwa asked him why he committed the crime, Kubeka shrugged and said he did not know what went on in his mind.

He said he was "showing some remorse" and asked his family to forgive him for what he did. He told the court he had no formal schooling and had worked as a potato hawker and part-time mechanic at the time.

In a written plea explanation, Kubeka said he had entered his grandmother's home through an unlocked kitchen door and found her sleeping on the floor.

"I then woke up the deceased and strangled her. I put her on top of the bed and raped her. After raping her I put a blanket on her and left," he said.

"I don't know why I have committed these offences... I know what I did was wrong. I regret my action and I am truly sorry about what I have done."

Kubeka's aunt Anna Sibiya said the family did not accept his apology as he had never shown any remorse or apologised to them. She testified that she had seen Kubeka running away from the house and had called him back to go inside with her. He was present when she found the body, but he did not say anything about what had happened.

Baqwa would sentence Kubeka on Wednesday.