Uyinene Mrwetyana was brutally murdered in Cape Town, where she was a first-year film and media student. Picture: Supplied

Cape Town - Department of Communications Minister Stella Ndabeni-Abrahams has ordered a probe into how the man who allegedly raped and murdered University of Cape Town student Uyinene Mrwetyana remained employed at the Post Office despite previous criminal convictions.

The 42-year-old man, who worked at the post office in Claremont, had previously been convicted of armed robbery, said the National Prosecuting Authority (NPA) in the Western Cape.

The NPA also said he had a rape case against him withdrawn.

NPA Western Cape spokesperson Eric Ntabazalila confirmed the two charges to the media.

"He's got a record of armed robbery, or what is called robbery with aggravating circumstances. There is also a case of rape that he had, but it was withdrawn. I don't have circumstances why it was withdrawn," he told Radio 702.

"It has come to my attention that the SAPO employee who allegedly assaulted and murdered Ms Mrwetyana had previous criminal convictions. As the shareholder representative of SAPO, I am deeply disturbed," said Ndabeni-Abrahams.

The accused who was arrested on Friday faces charges of rape, murder and defeating the ends of justice. He appeared in the Wynberg Magistrate's Court on Monday when the court heard that the accused confessed to the murder and led police to where her body was dumped.

The court was told by the prosecutor that Mrwetyana was raped and bludgeoned to death with a scale inside the post office.

The court ordered that the accused's name and photograph not be published.

The case was postponed to November 5.