Oscar Pistorius buried his head in his hands on Tuesday as a forensic expert gave graphic details of the gunshot wounds sustained by Reeva Steenkamp.

Mr. Dixon said the first bullet which hit Reeva - who claims to have mistaken her for an intruder and shot her through their bathroom door - in the arm was like "an instant amputation".

Pistorius then bent forward in the dock and put his hands over his ears as the expert described the impact of another bullet wound on the model's skull.

An earlier witness, Police Captain Christiaan Mangena, previously said Reeva was first shot in the hip, with a second shot missing, and the final two hitting her in the arm and the head.

However, the court in Pretoria were told by Mr. Dixon that he believed the first two shots hit her in the hip and arm in quick succession while she was close to the door, which backs the Paralympian's version he shot in quick succession fearing an intruder was coming out of the cubicle to attack him.

While the defense was trying to cast doubt on the prosecution's argument that Reeva had locked herself in the toilet following a row with the sportsman, prosecutor Gerrie Nel then called the integrity of their witness into question with his cross-examination, suggesting he was out of his depth in testifying about the lighting, sound and physical evidence.

The trial has now been adjourned until May 5.

Pistorius, who denies all charges, faces up to 25 years in prison if convicted of murder.