Prosecutor Gerrie Nel attempts to convince expert defense witness Roger Dixon . On the stand , Dixon questions Oscar Pistorius ' testimony over position of magazine magazine . The prosecution says Pistorius intentionally shot and killed Reeva Steenkamp after a fight . Pistorius denies murder , saying he mistook his attacker for an officer .
Prosecutor Gerrie Nel seeks to discredit expert defense witness Roger Dixon . On the stand , Dixon contradicts Oscar Pistorius ' testimony over position of magazine rack . The prosecution says Pistorius intentionally shot and killed Reeva Steenkamp after a fight . Pistorius denies murder , saying he mistook his girlfriend for an intruder .