Oscar Pistorius breaks down in tears

Oscar Pistorius broke down in tears after his defence team argued that the gunshots which killed girlfriend Reeva Steenkamp left her brain so "damaged" she couldn't have screamed.

The athlete's defence counsel Barry Roux landed significant blows against the testimony of Michelle Burger, a neighbor who claimed she heard Ms Steenkamp's "blood curling screams" followed by the sound gunfire in the early hours of Valentine's Day morning last year.

Mr Roux challenged her testimony signalling that "the amount of brain damage" inflicted on Ms Steenkamp would have reduced her cognitive functions to none as Mr Pistorius wept in the dock and covered his ears with his hands.

"What we know is that Reeva was locked inside the bathroom. We know, there is no dispute, that when the shots were fired, Reeva was in the toilet and the door was locked.

"You tell us from 177 metres you could hear that screaming," Mr Roux continued. "It was so distinct, what you could hear, that you could hear increased emotion, increased intensity?"

"That person, who had sustained that amount of brain damage [when the fourth bullet struck her in the head], would have no response, no cognitive function. There can have been no response, and yet you claim to have heard her screaming?" Mr Roux asked.

Dr Burger countered that the sound of the screaming could have carried from before the shot was fired and insisted she stands by her testimony- that she was woken by the sound of a woman screaming, followed by the sound of a man screaming for help, and then four gunshots, during which the woman's screaming continued, and faded away afterwards.

Mr Roux also sought to cast doubt over Burger's reliability as a witness, claiming her and her husband's statements given to police are so similar "one must have served as a template for the other."

Dr Burger countered that the statements were given in the form of answers to questions to police, and are merely "police writing style."

"If he [the police captain] is asking me about the sequence of events, if he asked me what time I went to bed, I told him, between nine and ten. My husband would have answered the same."

Mr Roux's assertion is that the sound of gunshot was in fact the sound of Mr Pistorius striking the locked bathroom door with a cricket bat.

"I really don't see that a bat and a gun shot sound the same," Dr Burger said. "A gun shot is extremely loud."

"Do you know what it sounds like when you hit a bat against a door?" Mr Roux continued.

"No I've never hit a bat against a door. But I know what a gun shot sounds like. If I hit a bat against a door in this court, and then pulled a trigger, I know which would be louder."

When asked for why Mr Pistorius would have shouted for help before the shots were fired, Dr Burger replied: "The only thing I can wonder is that it was a mockery, but I do not know. Mr Pistorius is the person who must answer that."

"You will even go so far as to call him a mockery, with no facts?" Mr Roux countered, pointing at Oscar Pistorius in the dock. "Just to not make a single concession that can help that man?"