An elderly woman, 82, and her son, 50, were attacked and severely assaulted on Friday on their farm near Petrusburg in the Free State.
According to Maroelamedia the Free State Police spokeswoman Thandi Mbambo. the mother and son were in the home on Lovedale farm when the power went off at about 7pm.
The boy, Willem Jacobus du Toit, went out to investigate when he was attacked by three unknown men.
Mbambo said Du Toit was dragged into the house where he and his mother were badly assaulted. Both victims were tied up and the suspects insisted on the safe.
Mbambo said the suspects fled on foot with a stolen firearm and two cell phones.
Marius Müller, national operations coordinator for AfriForum, said the mother and son were both taken to a hospital in Bloemfontein in serious condition after the incident for medical treatment.
No one has been arrested in connection with the incident.
Police are investigating a case of armed robbery, Mbambo said.