Star Olympian Oscar Pistorius faces a possible life sentence when he goes on trial Monday accused of murdering his girlfriend in a Valentine's Day shooting that shocked the world.
Facing the glare of a globally televised trial, Pistorius is expected to argue he shot his 29-year-old lover Reeva Steenkamp through a locked toilet door at his home believing she was an intruder. (Read: Judge rules most of Pistorius trial can be televised)
The 27 year-old South African superstar, whose strength overcoming disability inspired millions, will appear in the dock at the North Gauteng High Court in Pretoria to answer one charge of murder and three firearms charges. (Read: Pistorius surfed porn before girlfriend was shot: report)
The trial is slated to last three weeks, but will likely last longer as teams of lawyers weigh Pistorius's account of events, as the only surviving witness, against forensic and other evidence which the state says shows murderous intent.
Reeva's mother June will be among those looking on, according to uncle Michael Steenkamp. "What we have decided as a family is that my sister June will attend the trial," he told AFP.
If found guilty of premeditated murder Pistorius faces 25 years in South Africa's notoriously brutal jails, as well as instant international infamy and an abrupt end to his glittering sporting career.
The trial -- which has already drawn comparisons to that of disgraced American football star OJ Simpson -- caps a remarkable reversal of fortune for the sprinter, whose own testimony will not be televised.
The "Blade Runner" steps into court barely 18 months after hurtling across the finishing line in record time to win gold at the London Paralympics, securing the adoration of millions and his place in sporting history.
He was the first double amputee to compete in the Olympics and the Paralympics, winning medals at the Athens, Beijing and London games.
His fate now depends on a crack team of lawyers, forensics, ballistics and other experts who face South African state prosecutors still reeling from a protracted and humiliating bail hearing.
A year ago Pistorius walked free on bail as the chief detective on the case and prosecution's star witness Hilton Botha was sacked amid a scandal over fluffed evidence and his own attempted murder charge.
But Pistorius still faces an uphill task to convince Judge Thokozile Masipa -- who in a decade and half on the bench has spoken out strongly at violence against women -- that he had no intent to kill Steenkamp, a model and law graduate.
Deeply in love
According to Pistorius account of events, on the night of February 13, 2013 the couple had a "quiet dinner together" at his home on 286 Bushwillow Street, in the tightly secured Silverlakes estate near Pretoria.
"She was doing her yoga exercises and I was in bed watching television. My prosthetic legs were off. We were deeply in love and I could not be happier," Pistorius said in a bail affidavit.
In the "early morning hours" Pistorius woke up and went on to the balcony to fetch a fan and close the blinds.
"I heard a noise in the bathroom and realised that someone was in the bathroom. I felt a sense of terror rushing over me," Pistorius recalled.
Believing Steenkamp was in bed, Pistorius grabbed his 9mm pistol from under his bed and headed for the toilet. He "fired shots at the toilet door and shouted to Reeva to phone the police."
Soon after he realised Steenkamp was not in bed, he rushed back to the bathroom and used a cricket bat to break open the toilet door, only to find her "slumped over but alive."
"I tried to render the assistance to Reeva that I could, but she died in my arms."
Negligent or intentional
The prosecution is expected to argue this account is a fabrication designed to conceal Pistorius's guilt, while pointing to a history of reckless behaviour with firearms.
The state is likely to argue that Pistorius on two occasions fired a pistol in public, once through the sunroof of a moving car and months later at a busy restaurant in Johannesburg.
He is also accused of possessing unlicensed ammunition.
Above all they will try to show that regardless of who was behind the toilet door, Pistorius acted recklessly.
"There are basic principles that apply when you can use a firearm or any other weapon in self-defence," said Martin Hood, a lawyer not directly linked to the case.
The shooter must believe his or her life is in danger, "you must respond proportionally and you must respond immediately," said Hood.
"If you take those basic requirements and you apply them to the Pistorius case, it's very difficult for him to, excuse the pun, get out of the starting blocks because he shot someone behind a closed door."
The trial, which a court ruled on Tuesday can be broadcast around the world, is likely to put South Africa's legal system, as well as Pistorius on the stand.
"The justice system is still perceived as treating the rich and famous with kid gloves whilst being harsh on the poor and vulnerable," said Judge Dunstan Mlambo.
Broadcasting the bulk of the proceedings would help dispel these "unfounded perceptions," he said.
But in seeking out a maximum sentence, the prosecution will face a higher bar than the more obvious charge of culpable homicide, which could carry as little as a suspended sentence and a fine.