(WARNING: GRAPHIC TESTIMONY)Hannah Cornelius was hit so hard on the head that she would have died almost immediately, the pathologist who examined the Stellenbosch student's body told the Western Cape High Court on Tuesday."The skull is made of very strong bones. It is not easy for a skull to break or crack, unless a lot of power is used to break the skull," state pathologist Dr Deidre Abrahams testified.She was also stabbed in the neck with either a knife or a screwdriver and showed signs of severe genital and cervical injuries, with sand found inside that part of her body.Abrahams explained that clues, like the sand, showed that a victim was unprepared for what was about to happen, possibly being thrown to the ground, the sand entering the victim's body as the victim was penetrated."This is part of the overwhelming experience of the deceased," she said."This would have been a very painful experience to the person."READ: 'There's a person lying there' - tragic discovery of Hannah CorneliusHannah had bruises on her arms, her legs were scratched, probably from when her pants were pulled down, and she had a contusion on her lip.Abrahams submitted that it appeared that Hannah had been hit on the head twice with a heavy object, and that somebody had held the right side of her head while she was on the ground.She was hit so hard that her skull cracked and her brain was damaged.'Severe blunt head injuries'A large rock was on a table in the court and testimony on its relevance is expected later on Tuesday.However, earlier in proceedings, two technicians who found Hannah's body near a borehole they were repairing testified that they had used a rock to cover the borehole the night before they found Hannah. The rock they used had been moved when they arrived the next day to finish the work.Abrahams said a belt had been found around Hannah's neck, but that there was no sign of strangulation detected during the autopsy.The blows to Hannah would have been rapid, and the force, judging by the severity of the head injuries, meant she would have died quickly."The cause of death, therefore, was firstly the severe blunt head injuries," said Abrahams.ALSO READ: Stellenbosch cop recounts dramatic chase that led to arrest of Hannah Cornelius murder suspectShe had also been stabbed in the lower neck near the top of the green jersey that she was wearing. The jersey was inside out. That injury would also have been fatal as it had pierced a gland in the neck.Abrahams believed thought that it was the blows to Hannah's head that killed her.The prosecution led testimony from a number of police officers who had participated in collecting evidence and tracking down who might have killed her and attacked her friend Cheslin Marsh.'I saw a bump in the mattress'Marsh survived the attack with serious injuries. They had been pounced on by a group of men in the early hours of May 27, 2017, as they chatted in Hannah's VW Citi Golf on the corner of Jan Celliers and Bird streets in Stellenbosch.Sergeant Jerome Timmy testified that his labrador Ethan, trained at police dog school to detect bodily fluids and semen, had led him to condoms and condom wrappers at the scene where Hannah was found.Cloetesville police Sergeant Syster Pietersen testified that he had arrested Eben van Niekerk when he was sent to a house to look for him.He had found him asleep beneath a mattress and the base of a bed in the house he had been sent to."I saw a bump in the mattress," testified Pietersen. He lifted the mattress and there was the suspect, fast asleep. He said he had had to wake Van Niekerk.Geraldo Parsons, Vernon Witbooi, Van Niekerk and Nashville Julius face a string of charges, including murder, aggravated robbery, kidnapping and rape.Cornelius was threatened with a screwdriver, while Marsh was forced into the back seat of his friend's car at knifepoint.The trial continues.