Cloete and Thomas Murray were followed by a car and a motorcycle from Pretoria to Johannesburg and were watched for hours before they were gunned down just after 14:00 on 18 March on the N1 North just after the New Road bridge.
Thomas Murray, 28, was declared dead at the scene. Cloete Murray, 57, was struck at least once in the head and after being placed on life support at Netcare Sunninghill Hospital, died early on Sunday.
The funeral for the father and son will take place on 26 March.