Constables Cebekhulu Linda, Keamogetswe Buiks and Boepelo Senoge left Bloemfontein late on Thursday evening late.
They traveled to Polokwane, where Linda and Buys were deployed.
Senoge was on leave, but accompanied the couple because it is understood that she was romantically involved with Linda.
Researchers followed their movements from the free state of Gauteng.
In the early hours of Friday morning they stopped to fill at a gas station in Lenasia before they traveled to Centurion.
But just after 2 hours all their mobile phones, as well as the vehicle follow -up signals, stopped.
It is suspected that they crashed against the Hennops River, about 10 km from where researchers could find them for the last time.
The white VW polo in which they traveled still has to be restored while search and rescue teams continue to comb parts of the river.
Orrin Singh
www.ewn.co.za