Ntwaagae Seleka, Masoka Dube, Sipho Masombuka and Sapa
Members of the police force went on the rampage in separate incidents at the weekend killing relatives, friends and colleagues.
The worst of these happened in the Free State where a constable was arrested after he allegedly shot and killed two clerks and seriously wounded a police superintendent.
Captain Magda Muller said the incident took place on Saturday morning.
"The suspect [a constable] stopped the Ford Icon [in which the victims were being transported] about 10km from Heuningspruit on the N1, got out of the vehicle and started shooting in the direction of the passengers," Muller said.
Muller said the passengers managed to get out of the vehicle, but the constable continued shooting at them. A man and a woman were seriously wounded and died at the scene.
The superintendent, who was also seriously wounded but is now in a stable condition, was taken to the Kroon Hospital in Kroonstad.
She said the 26-year-old constable from Viljoensdrif police station had reported for duty a few hours earlier and booked out an R5 rifle, a 9mm pistol and a police vehicle.
Muller said the two clerks were identified as Remofiloe Tlhapane, in her mid-20s, and BT Bulunga, 31.
In Gauteng Vaal Rand police have launched a manhunt for a constable on the run for murder.
Police spokesman Captain Veli Mcera said the 34-year-old constable, who was based at Evaton police station, was wanted for allegedly stabbing to death his lover's 32-year-old boyfriend and wounding another man, aged 33, who was with the woman at the time on Saturday night.
Police said they would release the constable's name if he was not arrested within 48 hours.
Also in Gauteng, a critically wounded trainee police constable is under guard at a Pretoria hospital after killing his pregnant girlfriend before shooting himself.
This happened at Diepsloot, northwest of Pretoria, on Friday afternoon. Pretoria police spokesman Inspector Paul Ramaloko said it appeared that the two had quarrelled.
In Mpumalanga, police are looking for a constable who allegedly shot and wounded two people he accused of standing in his way on Saturday night in Nyongane.
The constable, who was off duty at the time is stationed at Nelspruit police station, is accused of shooting Oupa Maphanga, 49, and Psycho Ngoma, 30.
It is alleged that the policeman was traveling in a bakkie with his brother when he stopped next to a group of people standing near the road. The victims said the constable ordered them to make way for his vehicle. He opened fire when they did not move.