Anti-gang unit section commander Lt-Col Charl Kinnear was shot dead outside his home in Cape Town on Friday afternoon.
Kinnear, 52, was working on several high-profile investigations and was the investigating officer in an extortion case involving alleged underworld figure Nafiz Modack, the murder case of biker boss Tim Lotter and the murder case of Cape Town attorney Pete Mihalik.
Sources said they believed the attack on Kinnear was a hit. Photographs showed the policeman's body in the driver's seat of a white Toyota Corolla.
He appeared to have been shot through the window, which was smashed.