CAPE TOWN - The NPA will not respond to a request for comment regarding a documentary questioning the police case against Shrien Dewani, Western Cape director of public prosecutions Rodney de Kock said on Sunday.
"... It would be improper for the NPA to engage on the merits of the case," he told BBC: Panorama editor Tom Giles in a letter, sent at the beginning of September, and shown to the media on Sunday.
"To do so will be to subject Mr Dewani to a trial by media, a concept foreign to the Republic of South Africa and a practice that will violate Mr Dewani's right to a fair trial."
De Kock said the matter was sub judice.
"The proper forum to address this matter is a Court of law, not the media."
Shrien's wife, Anni Dewani, was shot dead in an apparent fake hijacking in Khayelitsha on November 14, 2010. Three men are already serving sentences for her murder.
Her 33-year-old husband Shrien, who has repeatedly denied masterminding a plot to kill his wife, is undergoing treatment in the United Kingdom for post-traumatic stress disorder.
He has been fighting extradition to stand trial in Cape Town for over two years.
The BBC One Panorama programme in the United Kingdom planned to air a documentary on Thursday looking at the criminal case against Dewani, according to its website.
The programme, titled "The Honeymoon Murder: Who killed Anni?" claimed to have obtained "secret police files" and commissioned forensic experts to review all the evidence.
According to the online preview, the experts plan to expose "fundamental mistakes" in the police investigation and the interpretation of forensic evidence.
Chief Magistrate Howard Riddle ruled in 2011 that Dewani should be extradited but he successfully appealed against this order, on mental health grounds.
The British Press Association reported in July that Riddle had ordered for Dewani to be extradited on the basis of a slow but steady recovery.
"It may be a long time before Mr Dewani is fit to plead, but he may be closer to that point," he was quoted as saying.
"It is not impossible that if returned now, then after a reasonable period of further treatment and assessment he will be found fit to plead and a trial can take place."
Agence France Press reported last month that Dewani launched an attempt to take his extradition case to the Supreme Court, arguing his mental health was too fragile.