JOHANNESBURG -  The regional court in Vereeniging heard that the boy, Amaro Jose, was gagged and then drowned in a boiling water becaue he would have been able to identify his family's assailants.

Patrick Petrus Radebe, 24, who was the family's gardener, and Sipho Mbele, 21, their domestic worker's son, and Sphiwe David Motaung, 20, pleaded guilty on Tuesday, reported Beeld newspaper.

Mbele and Radebe each pleaded guilty to three charges of murder and one charge of rape each.

Motaung pleaded guilty to house robbery charges.

The court heard that Mbele and Radebe raped Geraldine Viana before shooting her with her husband's firearm. The men then shot Tony Viana, who had been tied up after being assaulted with a panga and golf club, in the head. After that, the boy was drowend in the bath.

Beeld reported that the three men laughed while walking back to the court cells at the end of the hearing.

Sentencing will start on September 6.