<p>Oscar Pistorius' "primal instincts" kicked in when he shot dead his girlfriend Reeva Steenkamp because he was in a vulnerable and fearful state, his defence lawyer said at the athlete's murder trial on Friday. <br /><br /></p>.<p>Double amputee Pistorius, 27, is accused of murdering Steenkamp.<br /><br />The defence says Pistorius shot Steenkamp through a locked toilet door believing she was an intruder.<br />State prosecutor Gerrie Nel has spent the trial, which began in March, portraying Pistorius as a gun-obsessed hothead who deliberately shot Steenkamp, 29, four times through the door of the toilet.<br /><br />Defence lawyer Barry Roux said during his closing arguments that psychological evidence had proven the track star had a heightened fight response and naturally faces danger because of his disability.</p>
<p>Oscar Pistorius' "primal instincts" kicked in when he shot dead his girlfriend Reeva Steenkamp because he was in a vulnerable and fearful state, his defence lawyer said at the athlete's murder trial on Friday. <br /><br /></p>.<p>Double amputee Pistorius, 27, is accused of murdering Steenkamp.<br /><br />The defence says Pistorius shot Steenkamp through a locked toilet door believing she was an intruder.<br />State prosecutor Gerrie Nel has spent the trial, which began in March, portraying Pistorius as a gun-obsessed hothead who deliberately shot Steenkamp, 29, four times through the door of the toilet.<br /><br />Defence lawyer Barry Roux said during his closing arguments that psychological evidence had proven the track star had a heightened fight response and naturally faces danger because of his disability.</p>