A 39-year-old suspect will appear at the Bishop Lavis Magistrate's Court on Friday in connection with the murder of Lieutenant Colonel Charl Kinnear, 52.
Kinnear, who was attached to the Western Cape Anti-Gang Unit, was shot dead in front of his house in Bishop Lavis in Cape Town on Friday.
According to Hawks spokesperson Brigadier Hangwani Mulaudzi, the suspect was arrested in Gauteng on Wednesday and details surrounding the murder are still unknown.
"More arrests are not ruled out as investigations are still underway," Mulaudzi said.
The name of the suspect is known to News24 but he cannot be identified until he has appeared in court.
According to Netwerk24, the suspect is a former professional rugby player from Springs on Gauteng's East Rand.
Western Cape detectives reportedly took him in for questioning on Tuesday night.
The 39-year-old man, the son of a retired police colonel, was seemingly responsible for the tracking of Kinnear's cellphone, Netwerk24 reported.
Residents in Bishop Lavis told News24 that shots were heard at around 15:00 on Friday.
In a statement, national police commissioner General Khehla John Sitole said: "We are all saddened by this tragic untimely loss of Colonel Kinnear and his murder is a huge loss to South Africa and its people."
Police Minister Bheki Cele said Kinnear was "failed" by the police. The minister said this at a briefing in the Kinnear family's driveway on Saturday, after spending almost an hour with Kinnear's wife Nicolette and sons, Carlisle and Casleigh.
"I must say unfortunately, at the moment, there are more questions than answers ... but right now, as it stands, it does look like we have failed as the police. We could have done things better."
Cele said he would not hesitate to ask President Cyril Ramaphosa for additional resources, if needed, to track down Kinnear's killers.
Meanwhile, on the streets of Kinnear's beloved home suburb of Bishop Lavis, the local Community Police Forum (CPF) planned to hold a candlelight vigil outside the Kinnear family home on Thursday afternoon to honour him.