Journalists Jacques Pauw and Pieter-Louis Myburgh will not be presenting themselves to Durban North police station to make statements relating to material published in Pauw's best-seller The President's Keepers or in Myburgh's news articles published on News24.
This is confirmed in a letter that their attorney, Willem de Klerk, addressed to a colonel in the police, who is identified as the investigating officer.
"From the said telephone discussions it appears that Mr Pauw is regarded as a potential suspect related to material contained in his book. It further appears that Mr Pieter-Louis Myburgh is a potential suspect based on an article or articles he may have authored which appeared in the news media," the letter states.
"We record that, save for the above, you were not willing to disclose further details regarding the matters under investigation. We confirm your request that both Mr Pauw and Mr Myburgh present themselves at Durban North police station in order to answer questions and/or make statements to the matters under investigation," it continues.
"Our clients are not at this stage willing to answer questions or make statements but would prefer for the investigation to be completed first."
De Klerk further states that his clients would be willing to depose affidavits to that effect and will give their full cooperation to the National Prosecuting Authority should it decide to prosecute either Pauw or Myburgh.
"Our clients' decision not to make statements at this stage is based on their Constitutional rights and on legal advice. It does not imply that they are uncooperative in the matter."
Myburgh on Thursday said authorities were targeting him for what he had written relating to the Gupta family, corruption at Prasa and other exposs, but showed little interest in investigating the contents of the reports.
"There is no indication that the authorities are showing similar interest in what we have exposed," he told TimesLIVE. "I suspect it is related to the contents of Pauw's book and what I have written previously."
Myburgh also authored the book The Republic of Gupta, which detailed allegations of the grip the controversial Gupta family have on government and President Jacob Zuma.
Pauw was not immediately available for comment, but the publishers of his book reiterated that it stood by him and his work.
"We are communicating with the authorities through our attorney trying to find out more about the nature of the complaint," NB Publishers said on Thursday.
"We are willing to cooperate but stand by our author and our book. We are concerned about the lack of transparency from the authorities on this matter."
The South African National Editors' Forum (Sanef) on Wednesday said it viewed the actions as intimidation tactics.
"Our message as Sanef is very clear. We're not going to stay silent " journalism is not a crime," News24 quoted Sanef deputy chairperson Katy Katopodis as saying.
Police spokesman Brigadier Vishnu Naidoo, who was not immediately available on Thursday, told News24 that Pauw and Myburgh were not under investigation and that no case had been opened.