JOHANNESBURG - The family of murdered state witness Marius van der Merwe says he lived in fear for months and repeatedly warned them that he was being followed.
Van der Merwe, known as Witness D at the Madlanga Commission, was shot and killed outside his home in Brakpan last Friday.
His murder comes just weeks after he gave testimony at the commission, raising fresh concerns about the safety of whistleblowers and state witnesses.
President Cyril Ramaphosa has condemned the killing, saying government will intensify efforts to protect those who step forward to expose wrongdoing.
Van der Merwe’s sister, Natasha, says the family only realised the severity of the danger he was in after his death.
“I didn’t know the severity of the case until my brother got killed,” she said.
“On Saturday, when all the family went to the house and we switched on the TV, that's when we knew the severity of the case."
Natasha says her brother became increasingly cautious in recent months. Even simple family responsibilities, like visiting their mother after she suffered a stroke, became tense moments.
“I couldn't understand why he didn't want to visit our mother and I got furious and said our mother is asking for him.
"That's when he explained to me that he was being followed,” she said.
Natasha said he eventually visited his mother but was in and out quickly because he knew people were watching.
A few days before he testified at the commission, he told her directly that he had become a state witness. But the family avoided asking questions.
“We didn't ask questions, we knew what kind of work he did. He was secretive about his work."
The last time the siblings spoke was on 5 December.
Natasha says Marius insisted they only communicate on a secure personal line.
“He told me, ‘This is the only safe line we must use.’ He never answered his work phones because he knew they were tampered with.”
Their earlier conversations had already revealed the danger he faced.
When their mother was hospitalised in September, he sent Natasha a voice note saying that he was shot at the previous night.
Still, she says, the family refrained from probing further.
Van der Merwe, whose father had been a miner, became deeply involved in investigating illegal mining and zama zama activity.
Natasha says this mission put him in direct contact with powerful individuals.
“He wanted South Africans to see what was happening," she said.
She claims Marius told her that they had permission from government to protect our mines.
"He mentioned they have high authority, the right to protect our mines and to do their work with the zama zamas," she said.
Despite the environment he worked in, she insists he rejected corrupt dealings.
“Vlam believed in justice. If he didn't do what they expected of him to do, they would have wanted to silence him," she said.
"Vlam had a very strong nature, he stood by his rules."
She said Marius was a go-getter.
"People said he wasn’t living by the book. No.
"He had friends in the police and with other security people, he was connected.
"But corruption? He wasn't involved in that."
Two years ago, shortly after their father died, Marius confided in her that he had been pressured into doing something against his will.
Natasha believes her brother may have pleaded with his killers in his final moments.
“If I know my brother, I believe he begged them not to kill him in front of his wife and children.”
Van der Merwe's killing has renewed calls for better protection for whistleblowers and state witnesses, many of whom continue to work without adequate security despite exposing high-risk criminal and corruption networks.
Government says it will provide updates as investigations continue.