Grief: As Pistorius spoke of her daughter's final moments, Miss Steenkamp's mother June, who has for so long sat unmoved (left) in the public gallery, broke down in tears and covered her face with her hand (right)

He said he then went to investigate the noise, shouting in terror at the suspected burglar with his firearm trained in front of him.

'I got to the entrance of the bathroom at the end of the passage where I stopped screaming', he told the court. 

'At this point I was certain that the intruders were in the bathroom.

'I had my pistol in my right hand and peered into the bathroom.

'I didn't have much mobility on the tiles. I had my pistol raised to the corner of the entrance of the bathroom.

'I noticed that the bathroom window was open. I was with my back against the wall.

'I wasn't sure if the intruders were in the toilet or around the corner at that point.

'Then I heard a noise from inside the toilet that I perceived to be someone coming out of the toilet. 

'Before I knew it I had fired four shots at the door.

'I was still scared to retreat because I wasn't sure if there was somebody on the ladder or someone in the toilet.

He said he then went back to the bedroom and realised Miss Steenkamp wasn't there.

'I didn't want to believe it could be Reeva inside the toilet. I didn't know what to do. I kicked the door. I was crying out, I was screaming. I have never screamed like that.'

The Paralympian's sister, Aimee Pistorius (second right), cries as she hears her brother's account of the night he shot his model girlfriend

 

Emotional: The runner's aunt Lois and uncle Arnold wipe away tears as they listen to his evidence

 

Concern: Aimee, sister of Oscar Pistorius, attends his murder trial

ON THE MOMENT IT 'DAWNED ON HIM IT COULD BE REEVA IN THE TOILET'

'I retreated to the corner of the bed while talking to Reeva. She didn't respond. I lifted myself onto the bed.

'I felt if Reeva was there. I couldn't feel anything. I thought she had gone down on the floor.

'I kept my firearm pointing towards the passage. 

'It dawned on me that it could be Reeva in the toilet. I jumped off the bed and tried to see if she was hiding behind the curtain.

'I didn't want to believe that it could be Reeva in the toilet.'

When she did not respond Pistorius said he realised he may have made a terrible mistake and rushed back to the bathroom to break down the ldoor.

After hitting the door, he saw the key inside, unlocked the door and 'flung it open'. 

There, he found her fatally injured.

'I said "Oh, Reeva". I sat over her and cried,' the athlete testified sobbing loudly and putting his head in his hands and before letting out the barely inaudible cry: 'She wasn't breathing'.

After a brief adjournment, his lawyer Barry Roux came back to say his client was in no state to continue.

The case was adjourned until tomorrow.

Earlier, the Paralympian retched on the witness stand as he described the moments leading up to the shooting.

Pistorius recalled how he heard a window sliding open in his bathroom in the middle of the night, convincing him an intruder was breaking in and that he needed to arm himself.

'That's the moment that everything changed,' he said, his voice tense with emotion. 

'I thought that there was a burglar that was gaining entry to my home.'

'I placed the bigger fan in the bedroom. They were both still running. I closed and locked the sliding doors and drew the curtains.

'I came into the room. The only bit of light was an LED light on the amplifier where the TV cabinet is.

'I could see Reeva's jeans on the floor. I picked them up to place them over the LED light.

'It was at this point that I heard a window sliding open in the bathroom. I heard the window hit the frame.

'I thought that a burglar had got into the house. I think I initially just froze. 

'I interpreted it as someone getting into the bathroom.

'That's the moment that everything changed.

'The first thing that ran through my mind was to protect Reeva and I and to get my gun.

He said he 'rushed as quick as I could' with his hand out in front of me, at times touching the floor before grabbing his firearm from underneath the bed.

Denial: Pistorius's ex-girlfriend Samantha Taylor sent this tweet seemingly in response to claims by the Paralympian in court that she may have set up a fake social media account to allegedly send hate messages to Miss Steenkamp

'NOISE THAT CHANGED EVERYTHING'

'I heard a window sliding open in the bathroom. 

'I heard the window hit the frame.

'I thought that a burglar had got into the house. I think I initially just froze. 

'I interpreted it as someone getting into the bathroom.

'That's the moment that everything changed.

'The first thing that ran through my mind was to protect Reeva and I and to get my gun'

'At that point I just wanted to put myself between the person who had gained access to my house and Reeva.

'I slowed down and had my firearm extended in front of me. 

'I whispered to Reeva to get down and phone the police. 

'As I entered where the (bathroom) passage is, I was overcome with fear. I screamed and shouted to the person to get out of the house. I didn't have my legs on.

'Just before I got to the passage I heard a door slam. It could have only been the toilet door.

'It confirmed that there was a person or people inside the bathroom.'

Pistorius then slumped forward and appeared to be sick as an autopsy picture of Miss Steenkamp was accidentally shown to the court.

Pretty: The court was shown this picture which the 29-year-old model sent Pistorius in one message showing her hair and make-up done before an event. He told her she looked 'amazeballs'

 

Earlier, Pistorius fought back tears in the witness box while reading a string of heated phone messages Reeva Steenkamp sent him less than three weeks before he killed her.