Olympic and Paralympic athlete Oscar Pistorius will find out next month if he is has been found guilty of murdering his model girlfriend, after the lead prosecutor in the case urged him to "face the consequences".

The South African sprinter will be brought back to the courtroom in Pretoria on September 11, where judge Thokozile Masipa and her two assistants will announced whether he was responsible for the cold-blooded killing of Reeva Steenkamp on Valentine's Day last year.

Pistorius's fate is in the hands of only the country's second black high court judge since the end of apartheid.

Ms Masipa has four weeks to pore over 4,000 pages of evidence before delivering her verdict in front of the world's media.

The fallen sporting hero, nicknamed the Blade Runner, has denied murdering Ms Steenkamp at his mansion in a gated village in Pretoria.

Pistorius claims he mistook her for an intruder when he fired a gun through a locked toilet door in self-defence.

State prosecutor Gerrie Nel, known as "the pit-bull" for his aggressive cross-examination of witnesses - including Pistorius, who was reduced to tears - portrayed the sportsman as a gun-obsessed hothead.

He concluded his summing up by reiterating his claim that the athlete deliberately shot the 29-year-old four times as she was taking refuge in the toilet after an argument.

Mr Nel said: "He knew there was a human being in the toilet. That's his evidence. His intention was to kill a human being. He's fired indiscriminately into that toilet. Then m'lady, he is guilty of murder. There must be consequences."

Earlier this week, Mr Nel accused Pistorius of telling "a snowball of lies" and had called for the runner to be convicted of intentional murder, a crime that can attract a life sentence.

Under South African law, culpable homicide carries a possible sentence of about 15 years.

Barry Roux, for the defence, said evidence had proven the track star had a heightened fight response because of his ­disability and was in a terrified and vulnerable state when he shot Ms Steenkamp.

Mr Roux added: "You're ­standing at that door. You're vulnerable. You're anxious. You're trained as an athlete to react. Take all those factors into account,"

He argued that Pistorius felt exposed because he was standing on the stumps of his legs.

"He stands with his finger on the trigger, ready to fire when ready. In some instances a person will fire reflexively," he continued. "That is your primal instinct."

Mr Roux also argued that ­prosecutors had only called witnesses who supported their argument and not other key people, including police officers, who he said would have undermined their case.

Pistorius also faces three ­separate charges, including two counts of discharging firearms in public and possession of illegal ammunition, all of which he denies.

Mr Roux said the trial should only ever have been on the charge of culpable homicide, because he said Pistorius had clearly shot Ms Steenkamp by mistake.

Closing arguments centred on evidence from witnesses who say they heard a woman scream before a volley of shots, supporting the prosecution's position that the couple had an argument before Ms Steenkamp was killed.

Mr Roux went through the early morning of the shooting minute by minute during his wrapping-up, arguing that the witnesses were confused and contradictory about the sounds they heard.

He also spent time analysing photos he said proved the police had moved items in the couple's bedroom, countering a key claim by Mr Nel that images of the room proved Pistorius's version of the events was impossible.

However, Pistorius's chief accuser said his evidence was "devoid of any truth" and that the athlete contradicted himself when he said during cross-examination that he fired both accidentally and deliberately.

In the absence of a jury, Ms Masipa will either accept or reject his version of events.

The fathers of both Pistorius and Ms ­Steenkamp have been in court this week. The athlete's aunt embraced Mr Steenkamp before the trial resumed yesterday.