Oscar Pistorius expected to testify on Friday in murder trial

For three weeks, the evidence has been dominated by Oscar's guns, Oscar's cricket bat, Oscar's screams and Oscar's neighbours.

Now it is time for the court to explore Oscar's mind as a new phase of the Pistorius trial begins.

On Friday, his attack dog lawyer Barry Roux will lead questioning as the defence case is opened.

He will be forced to switch gears - teasing evidence from witnesses he has decided to call, rather than blitzing those placed in front of him by prosecutors.

Barry Roux, Pistorius' defence lawyer. Credit: Reuters

His challenge will be to replace the world of fast cars, firearms and bravado presented by state lawyers, with one that shows the impact of fear, anxiety, disability and celebrity, as the defence lawyers have suggested.

And for both sides, the most important witness will be Pistorius himself, who is expected to testify in the morning.

Millions of viewers will watch - but they might only hear his evidence if his lawyers request that only the sound of his testimony is televised. But the opinions of armchair jurors don't count.

Only Thokozile Masipa - the crime hack-turned-judge - will decide whether Pistorius is guilty or not.

We cannot know if she is already forming an opinion as we pass the half-way point of this trial - perhaps it would be irresistible not to. But she has weeks of forcefully-made testimony to assess.

Oscar Pistorius and Reeva Steenkamp. Credit: Press Association

She must consider the ballistics and forensics evidence gathered by South African detectives, and whether it was compromised by shoddy police work; Whether the screams that neighbours heard were of Reeva Steenkamp before she was killed, or whether the high-pitched squeals came from Pistorius himself; Whether an angry text message she sent him reveals a fractious relationship, or whether the kisses and pet names he sent back show a loving one.

With some weeks before a verdict is delivered, many viewers have told me their 'hunch' about this case. Of course, Judge Masipa will have to be far more certain before making her decision.

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