Pretoria: “We cannot [call] eyewitness evidence because the one witness we would want to call is dead.”

The prosecutor’s statement on day 20 of the Oscar Pistorius trial may have sounded ominous, but Gerrie Nel nonetheless declared he would be able to prove the athlete murdered his girlfriend Reeva Steenkamp because his “version is a lie”.

The international track star sat in the witness box for five days last week, three of those under intense cross-examination from the prosecutor, who alleges Pistorius' version of events is “so improbable that nobody will ever think it’s reasonably possible”.

Pistorius has repeatedly said his “life is on the line” but the prosecutor’s focus has been on his credibility, accusing him of lying, tailoring his evidence and blame-shifting, and refusing to accept responsibility for his actions.

He also articulated the specific nature of the state’s case for the first time, saying he will prove that the screams heard by witnesses in the lead-up to the Valentine’s Day shooting came from Reeva Steenkamp as she ran away from the Olympian in a row.

“I will build my case to say that when you got up, there was an argument and she ran away screaming,” Mr Nel said.

“It’s not true, my lady,” said Pistorius, addressing Judge Thokozile Masipa.

In painstaking questioning, Mr Nel pushed Pistorius to be far more detailed about his account than ever before, using his answers to highlight what he says are the flaws in his case.

In particular, he analysed the runner’s precise movements from the time he claims he awoke in the early hours of February 14 and retrieved two fans from the balcony, closing the sliding door and curtains before hearing a noise in the bathroom. Despite being no more than a metre from where he says Ms Steenkamp lay, also awake, Pistorius maintains the model said nothing and soundlessly left the bed as he brought the fans into the room.

Pistorius says it was “pitch black”, he had his back to the bed, and “the fans were blowing in my face”.

However, Mr Nel pointed out that there was clearly enough light for the athlete to be able to see Reeva’s denim jeans on the floor of the bedroom, because the next thing he claims to have done was pick them up and cover an LED light on an amplifier, plunging the room into “total darkness”.

Expressing disbelief at Pistorius' version of events, Mr Nel accused of him of answering the questions to suit the evidence available, and introducing new details never previously revealed.

In a police crime scene photo shown to the court, the bed’s duvet is lying on the floor, and Mr Nel asked how it got there.

Pistorius blames police for moving it; saying when he got out of the bed the duvet was on it, adding that it was covering the lower part of Reeva’s legs.

“Ah, so [there was enough light that] you saw that,” the prosecutor commented. “Keep trying, Mr Pistorius, it’s not working,” Mr Nel thundered as the day’s evidence drew to a close.

Earlier, Pistorius had appeared dogmatic in the face of questions about the incident at a Johannesburg restaurant when a gun he was handling discharged, the bullet narrowly missing a friend’s foot and other diners.

He has pleaded not guilty to that charge, saying his finger was not on the trigger and he was in fact trying to ensure it was safe when it went off in his hand. This is in spite of evidence from a firearms expert that the gun could not be fired unless the trigger was pulled.

On this topic Pistorius made a notable slip, the prosecutor swooping to accuse him of mixing up his lies.

“I didn’t have time to think,” the athlete said of the restaurant incident.

Mr Nel pounced immediately: “Ahh, so that’s one of your defences.”

He was referring to the athlete’s evidence from the previous day, in which he used the same words to describe the shooting of Ms Steenkamp, believing she was an intruder in his toilet.

The case continues.