Oscar Pistorius trial: 'Bull terrier' takes centre stage

Gerrie Nel: Reputation for being a ruthless and merciless prosecutor

Oscar Pistorius felt first-hand the bite of prosecutor Gerrie Nel minutes into his cross-examination at his murder trial.

Mr Nel is known as "the bull terrier" in court circles, and now the whole world is beginning to see why.

He has a reputation for being ruthless and merciless in his bid to get to the truth.

When asked by Mr Nel about his stature as a role model, the Paralympic gold medal winner replied: "I think I was. I made a terrible mistake."

And that is when Mr Nel pounced.

"You made a mistake? You killed someone. You killed Reeva, that's what you did.

"Say: 'Yes, I shot and killed Reeva Steenkamp,'" he demanded.

"I did," Mr Pistorius replied, in a barely audible voice.

It was a sign of things to come.

Graphic moment

Later Mr Nel showed the court a picture of Ms Steenkamp's head after the shooting. It was possibly the most graphic moment since the start of the trial.

Gasps and sighs filled the courtroom as Mr Nel thundered on.

"Look at it," he shouted at Mr Pistorius.

The athlete could not.

Through tears, he told the court he had cradled Ms Steenkamp's head and remembered how it had looked - he said he was "tormented" by it.

But Mr Nel was unrelenting.

He described Ms Steenkamp's head as having "exploded" - just like a watermelon Mr Pistorius had shot at a shooting range.

The prosecutor was referring to a video he played in court which showed Mr Pistorius firing at the fruit.

With laughter heard in the background of the video, Mr Pistorius is heard exclaiming: "It's softer than brain… it's like a zombie stopper."

The athlete says he now regrets making those comments.

'Anything goes'

Some have raised questions about Mr Nel's aggressive approach, but as respected South African legal expert Llewellyn Curlewis puts it: "This is what happens in court every day."

This is the best and worst of the criminal justice system on display.

"Cross-examination is the biggest single way to get to the truth of the matter," says Mr Curlewis, president of the Law Society of the Northern Provinces of South Africa.

"Anything goes. The accused's lawyer is there to object if there is a need."

Mr Curlewis explains that at any point the judge can intervene if she believes the witness is being badgered.

However, as this is a serious criminal matter, she will also not want to be seen as interfering during cross-examination - the crucial point where cases are often made or broken.

Mr Curlewis says justice must be served and sometimes that means through extreme means.

Mr Pistorius sometimes gives elaborate answers in court - to the annoyance of the prosecutor.

He was more composed in court today - his third day on the stand - except for a few moments of crying.

Mr Nel has begun pointing to a few alleged inconsistencies in his version of events in the early hours of 14 February 2013 when he shot dead his model girlfriend Reeva Steenkamp. Prosecutors say he intentionally killed her after a row, but Mr Pistorius insists he mistook her for an intruder.

Mr Nel is comparing Mr Pistorius' bail application (made last year) with his plea explanation (made when the trial opened) and his testimony this week.

In the same way that the athlete's lawyer picked apart the testimony of state witnesses, so Mr Pistorius can expect the same treatment from Mr Nel.

When the grisly photograph of Ms Steenkamp's head was shown, her mother, June Steenkamp, sat quietly and looked on as the image appeared on the screen.

The prosecution had apparently warned her prior to using the image, explaining the importance of using shock tactics.

She told reporters later she understood this approach.

'Not surprising'

The athlete's family, who were clearly taken by surprise, were not happy.

During an adjournment, family members could be seen speaking to his lawyers.

They felt the display was uncalled for. Mr Curlewis does not agree.

"I was not surprised whatsoever," he says.

"I would have been surprised if he hadn't. In fact, we should expect more pictures from the crime scene."

Due to the nature of many of South Africa's violent crimes, seeing images of brutalised and even mutilated bodies is not uncommon during court proceedings.

The only difference here is that this case is being broadcast to the world, so the barometer for what is and is not appropriate varies.

This was always going to be a gamble when inviting the world into the courtroom.

"It was unfortunate but it wasn't Mr Nel's doing," says Mr Curlewis.

This is what the men and women working in the country's legal system are faced with every day.

The justice system is under pressure to dispel any perceptions that Mr Pistorius will be treated differently because of his celebrity.

They want to show that he is equal in the eyes of the law, part of the reason why the media is being allowed to broadcast this case live - a first here.

South African courts pride themselves on their independence - a reputation they guard jealously.

While there will be uncomfortable moments for all concerned, Mr Curlewis says the accused has his lawyers to defend him if they feel he is being treated unfairly.

Apart from that, this is a fight for the truth - and at times it will get ugly.