Oscar Pistorius is to learn this week how long he will spend in prison for the crime of murdering his girlfriend with four bullets fired through a closed toilet door.

A sentencing hearing at the high court in Pretoria in South Africa starts on Monday and is expected to be be the final chapter in an extraordinary story that attracted intense worldwide attention.

The 29-year-old Olympic and Paralympic sprinter, who has spent recent months under house arrest at his uncle’s luxurious home in the city, could be in jail by the end of the week, with the prospect of about 15 years or possibly more behind bars.

Pistorius won global fame and fortune when he reached the semi-finals of the 400m at the 2012 Olympics. A double amputee below the knee from 11 months old, Pistorius inspired millions around the world with his determination to reach the highest levels of sport. His success attracted lucrative endorsement contracts and sponsorship deals from major brands.

But in February 2013 Pistorius fell spectacularly from grace when he killed his girlfriend Reeva Steenkamp, a model and law graduate.

Initially found guilty only of culpable homicide, or manslaughter in British law, and sentenced to five years in prison, he was convicted of murder after an appeal by state prosecutors last year. The former athlete has exhausted almost every legal option available to him.

“There is the theoretical possibility that he could appeal a sentence but … an appeal would not generally be admitted unless [the sentence] is shockingly inappropriate,” said David Unterhalter, a professor of law at the University of Cape Town and a leading advocate.

Tens of millions around the world followed the 2014 trial of Pistorius. Almost every minute of more than 40 days of psychological drama, intense emotion, police procedural and legal argument was broadcast live on South African television, and massively amplified by social media.

In South Africa the interest in the killing and its aftermath bordered on the obsessive. “People took time off work and watched the action. Workplaces came to a standstill. There were dedicated TV channels and ratings for anything else plummeted. Day after day, week after week, it was on the front pages. The story was just so compelling. The guy was a national hero and worshipped, and he became a national villain,” said Mondli Makhanya, a prominent South African journalist.

The killing and the trial also held a mirror to South Africa more than 20 years after the end of apartheid and the coming of democracy at a time of widespread disillusionment at a perceived failure to achieve the lofty goals of that time have not been achieved.

“In the same way that [Nelson] Mandela was the symbol of the country in the glorious years of generosity and pragmatism and all those good things, Pistorius … was a national icon of whom everyone was proud. His cataclysmic fall was a metaphor for broader disappointed dreams,” said John Carlin, who attended the trial and is the author of a book on the former athlete.

Though one South African commentator described the country as “heartily sick” of the case, every twist and turn is still being picked over. Pistorius’s family has responded angrily to a new book, published in April, claiming forensic evidence from the trial showed the athlete had attacked Steenkamp shortly before shooting her dead. The family dismissed the book as the work of “amateur forensic hobbyists”.

Days later came the news that ITV, the British network, would broadcast an interview with Pistorius, his first since the murder, in which he would speak about the night he murdered his girlfriend and be questioned about the case. It will be screened later this month. A feature-length film is also planned, as well as a three-part South African TV documentary based on a bestselling book about the murder.

Initially the prosecution had argued that Pistorius had deliberately killed his girlfriend out of jealousy and anger. Pistorius, who frequently broke down in court, denied the accusation , saying he was deeply in love with her and believed he was protecting her when he shot through the toilet door because he thought an intruder was hiding there.

The trial judge found there was no evidence that Pistorius had wanted to kill Steenkamp but found him guilty of the lesser crime of culpable homicide, as he had acted “too hastily and used excessive force”.

The verdict and sentence – five years in jail, of which only one would be served before the athlete was bailed – prompted outrage among campaigners against rape and domestic violence in South Africa and surprise among many legal experts.

The trial judge was criticised for failing to answer the key legal question of whether any reasonable person should have foreseen that firing so many bullets through a door was likely to cause death, whoever was thought to be on the other side.

The appeal court felt Pistorius must have known that he was likely to kill someone and overturned the manslaughter verdict. Describing Steenkamp’s death as “a tragedy of Shakespearean proportions”, the appeal judges said the accused ought to have been found guilty of murder.

As Pistorius had already been released under house arrest at his uncle’s residence in October 2015, before the state’s successful appeal, he did not return to prison.

A subsequent attempt by Pistorius’s legal team to appeal against the murder conviction was blocked in March by the constitutional court, South Africa’s highest judicial authority.

In the hearings this week the former athlete’s lawyers are likely to argue that his double amputation has made him psychological fragile, inducing a deep anxiety and a tendency to overreaction. They are likely too to emphasise his work with charity in an effort to reduce the sentence.

The first trial revealed Pistorius’s taste for guns and fast cars as well as his short temper. “For the prurient there will be a privileged view in his psychological makeup. The defence will be looking to show that he is a paranoid personality prone to this kind of behaviour. Now the issue is not whether is he guilty of murder the perspective is slightly different,” said Unterhalter.

Prosecutors may call their own witnesses. Steenkamp’s father, Barry, could give evidence for the first time.

One further twist is that as the hearing this week is effectively a continuation of the original trial, the same judge will preside. Thokozile Masipa, a 68-year-old former journalist who was only the second black woman to be appointed to the high court, was praised for her calm authority despite her controversial original verdict.

Observers say that, amid all the negative reflections on South Africa prompted by the Pistorius saga, one positive element has been the apparent strength of the country’s justice system. “The South African justice system has come out of this very well. The trial was conducted in an intelligent and mature way that was impressive by any world standards,” said Carlin.

Makhanya said it was unlikely that Pistorius would be forgotten, even if jailed. The Steenkamp family has made efforts to keep the public focused on the killing, as have campaigners against domestic violence and abuse. “It will be with us for a long time to come,” Makhanya said.

History of a champion athlete turned murderer

1986 Oscar Pistorius is born in Sandton, South Africa, with no fibulas. His lower legs are amputated when he is 11 months old

2004 The novice athlete smashes the 200m world record at the Athens Paralympics

2007 Pistorius wins an award at BBC Sports Personality of the Year

2008 At the Beijing Paralympic Games Pistorius wins the 100m, 200m and 400m titles. Launches campaign to participate in the Olympics

2012 The athlete reaches the 400m semi-finals at the London Olympics

February 2013 Pistorius shoots Reeva Steenkamp, his girlfriend, dead at their home in Pretoria

August 2013 He is charged with premeditated murder and possession of unlicensed ammunition

September 2014 Pistorius found not guilty of murder but guilty of culpable homicide, or manslaughter

October 2014 Sentenced to five years imprisonment, of which one will be served in jail before he is eligible for parole. He gets a three-year suspended sentence on the charge. Pistorius begins sentence

October 2015 Released on parole from Kgosi Mampuru prison to serve the rest of his sentence under house arrest at his uncle Arnold’s home in a wealthy suburb of Pretoria

December 2015 Manslaughter conviction upgraded to murder by supreme court of appeal

March 2016 Pistorius denied permission to appeal to constitutional court

June 2016 Sentencing hearing for murder