Domestic servants murder boss, wife and son

Thus go the story: These three men(right) broke into the house in Walkerville, Johannesburg, South Africa, assulted and shoot dead Tony Viena (right), brutally raped and killed his wife Geraldine (right) and then went on to tie up and gagged their sobbing son - Amaro (second left) and pushed him into a bath of extremely  hot water and drowned him.

In case your wondering who they are, they all are domestic servants to the dead Tony Viena. The family gardener Patrick Petrus Radebe, 24, David Motanug,21, and their domestic servant's son. Sipho Mbele, 21 all pleaded guilty of the three charges murder and one charge of rape each.   

Now tell me, what do you think should be done to them as they were reported to have returned to their cells...laughing!