Police divers have retrieved the back part of the VW Polo in which the three constables were travelling and their bodies later found in the Hennops River.

The part had been missing when the crew retrieved the rest of the vehicle on Thursday.

The vehicle is a crucial part of the investigators probe into what happened.

However, authorities say they are still investigating a case of culpable homicide.

The three officers will be remembered at a memorial service on Tuesday and their funerals will take place on Thursday, Friday and Saturday next week.