Police have arrested a suspect believed to be the gunman who killed Marius van der Merwe.

Van der Merwe was known as Witness D during testimony at the commission of inquiry where he spoke about corruption.

A specialised police task team made the arrest as part of investigations into cases linked to the commission.

The team was set up by National Police Commissioner General Fannie Masemola on the instructions of President Cyril Ramaphosa.

Keep up with the latest headlines on WhatsApp | LinkedIn

South African Police Service national spokesperson Brigadier Athlenda Mathe said the arrest followed days of investigation.

She said the team obtained a warrant of arrest earlier this week after gathering what investigators described as overwhelming evidence.

Police arrested the suspect on Saturday, 14 March 2026.

Mathe said investigators are continuing their work and are carrying out search and seizure operations at several addresses linked to the suspect.

"Investigators are currently conducting search and seizure operations at several addresses linked to the suspect," said Mathe.

Police have also seized a vehicle believed to have been used during the murder.

The suspect is expected to appear in the Brakpan Magistrate's Court on Monday, 16 March 2026.

Van der Merwe was a former officer of the Ekurhuleni Metropolitan Police Department and the owner of a private security company.

Before his death, he made serious allegations about corruption and an alleged cover up involving members of the metro police during his testimony at the commission.

Van der Merwe was shot and killed outside his home in Brakpan in December shortly after appearing before the commission.

His murder raised concerns about the safety of whistleblowers and witnesses who take part in sensitive investigations.