Cornelius and Marsh were chatting in a blue Volkswagen Citi Golf, which had been given to Cornelius by her 91-year-old grandmother, when they were approached by four men.
Marsh was thrown into the boot of the vehicle while Cornelius was forced into the back seat, police said.
The pair’s belongings were stolen before the university students were taken to an undisclosed location and beaten with bricks. Marsh told police that he only survived by throwing himself over a wall to escape his captors.
A witness who found Marsh told News24 that he was ‘barefoot and covered in blood, completely disorientated and didn’t know where he was’.
Marsh suffered head injuries and a broken arm in the attack and is recovering in the hospital.
Meanwhile, Cornelius’s body was found at 8.30am on Saturday.
Police say she had been stabbed several times before being strangled. Her captors are also accused of raping her.
Two suspects were arrested on Saturday following a high-speed chase in the hijacked Golf.
The men were seen on CCTV leaping over a ditch to evade authorities before eventually being caught. A third male suspect was later arrested.
Two of the men have been identified as Vernon Witbooi, 32, and Geraldo Parsons, 26.