Former Government Communication and Information System boss Themba Maseko has told the inquiry into state capture that there are more former and serving directors general who can help the commission uncover the extent of the Guptas' influence on government but they fear losing their jobs.
Maseko said they could provide details of the politically connected family's influence on government tenders and the conduct of Cabinet ministers.
Maseko started testifying at the inquiry headed by Deputy Chief Justice Raymond Zondo on Wednesday.
He is the fourth witness after former ANC MP Vytjie Mentor, former deputy finance minister Mcebisi Jonas and acting chief of procurement Willie Mathebula.
Maseko started his testimony talking about a 2016 memorandum signed by 27 former directors general demanding a commission of inquiry into state capture.
He said at the time serving directors general did not sign the document fearing "reprisals including losing their jobs".
Lawyers urged to get names from Maseko
"I am convinced there are a number of senior public servants and middle managers who have had experiences with a number of individuals, including the Gupta family or pertaining to the conduct of their political bosses, who have information, who can be willing to give information to the commission," Maseko said.
Zondo has repeatedly expressed concern that too few people have come forward to provide information to the commission.
He urged the legal team to get names from Maseko to contact the individuals to ask them to come forward.
Maseko said in 2016 when they penned the hard-hitting memorandum, people were fearful.
He said delays in the commission being set up also contributed to interest "fading away".
"The political climate has somewhat changed...there might just be a willingness to speak. At the time there was plenty evidence that those who spoke against certain practices in government were dealt with and left the service," he said.
Accused of being naïve
Maseko gave as an example an instance where the heads of intelligence who had penned a letter warning that the Guptas were a security threat subsequently lost their jobs.
Maseko was the only person to submit evidence to the ANC's internal probe into state capture.
He said at the time people thought he was "naïve" to think it would yield anything.
"I know friends and comrades thought I was being extremely naïve that the process would yield anything," he said. However, he told the commission he went ahead because he believed the "issue was serious enough and should be dealt with politically first and then state agencies including prosecutions could follow".
The ANC's national executive committee initiated the failed probe after Jonas revealed he had been offered R600m by the Gupta family if he took the job of finance minister.