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• Pistorius' story under intense scrutiny
• Pistorius relives moment he pulled trigger
In both shootings, Pistorius said, he "didn't have time to think" about what he was doing. "Didn't have time to think?" the prosecutor asked mockingly. "We had that yesterday. That's one of your defences."
Pistorius said Reeva Steenkamp was "exaggerating" when she accused him of throwing tantrums in front of their friends. He said he had been "upset" when she accused him of picking on her, but rejected Mr Nel's suggestion that he was calling his dead girlfriend a "liar".
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In a second day of intense cross-examination, Pistorius claimed that despite being less than 6ft away, he did not see or hear Miss Steenkamp get out of bed moments before he heard a noise from the bathroom that he took for an intruder. But he said that he did see her jeans on the floor in the bedroom he described as "pitch black" and was able to describe the position and movement of the duvet on the bed.
Asked how Miss Steenkamp could have got out of bed and past him in the confined space of the room without him noticing, he explained his senses were blurred by the noise of the fans and that she must have rolled to the other side. "Your version is a lie," Mr Nel said. "Impossible."
Watch: Tough cross-examination
Asked how the fan, the duvet and the curtains were in different positions in police photographs to where they should have been from his account, Pistorius suggested police had moved all three. "You keep trying but it's not working Mr Pistorius," Mr Nel told him. "Your version is so improbable that nobody would ever think it's reasonably possible."
The athlete's legal team frequently complained to the judge about Mr Nel's tactics, and Pistorius tearfully pleaded with the judge that he was "confused" and did not understand the lawyer's abrasive questions.
Photo / AP
The prosecutor spent much of the day seeking to paint 27-year-old Pistorius as an egotistical and weak character who sought to blame all those around him for his misfortunes. "Your life is just about you," he told the athlete, after reading messages he sent to Miss Steenkamp after a row over a friend's engagement party. "I had to. I had to... It's all about you, Oscar Pistorius."
He reread the apology delivered in court by Pistorius to Miss Steenkamp's family on Monday, before accusing him of offering it too late and for purely selfish reasons. "Why would you create a spectacle in court, in the public domain, in the public eye?" Mr Nel asked. Without waiting for a reply, he continued: "Again, you never thought about them, sitting in the public gallery of the court hearing that. You thought about Oscar Pistorius."
Watch: Pistorius had been taking anti-depressants
"I didn't think they were ready," Pistorius stammered in response, adding when challenged to apologise properly: "I am terribly sorry I took the life of their daughter."
Pistorius claimed that his former lover Samantha Taylor was "lying" when she said he had screamed angrily about her and about the suggestion he had once fired a gun through a car sunroof.
Asked why he had not pleaded guilty to the charge that he was in unlawful possession of ammunition found in his safe when his account appeared to admit he was, he said it was on the advice of his legal team. "It's the third occasion that you blame your legal team because you won't take responsibility," Mr Nel said.
Asking Pistorius later about a further example of alleged gun negligence that he sought to brush off, Mr Nel remarked that it was "the strangest day". "You just don't take responsibility for anything. Why can't you say 'it's wrong'?" he said.
The case continues.