South African athlete Oscar Pistorius returns to court for sentencing after being convicted of killing his girlfriend, Reeva Steenkamp.
Pistorius was found guilty of the culpable homicide of Ms Steenkamp last month but he was cleared of murder.
Judge Thokozile Masipa is expected to hear legal arguments and testimony for several days before passing sentence.
Pistorius faces up to 15 years in jail, although Judge Masipa could suspend the sentence or only impose a fine.
She said the athlete had acted "negligently" when he shot his girlfriend through a toilet door , but in the "belief that there was an intruder".
The Paralympic sprinter had strenuously denied murdering Ms Steenkamp after a row on Valentine's Day last year, saying he shot her by mistake.
Ms Steenkamp, a 29-year-old model and law graduate, was hit three times by bullets shot through a toilet door by Mr Pistorius at his home in the capital, Pretoria.
The judge said the state had failed to prove he intended to kill.
Analysis by Andrew Harding, Africa correspondent, Pretoria
There is a very real chance – backed up by precedent – that Pistorius could be given no jail time at all.
The judge could argue that he is a first-time offender who has shown genuine remorse. But given his criminal misuse of a firearm, what sort of message would that send to the public?
And – this is unanswerable, I suppose – would it even be in his own best interests to serve no prison time?
Would the public here and abroad welcome him back into society, and what sort of stress would he find himself under?
Having given Pistorius the benefit of the doubt in reaching her verdict – and taken plenty of flak for it – Judge Masipa may choose to lean the other way in sentencing.
The athlete, who has been on bail since the verdict, was also found guilty on a charge of negligently handling a firearm that went off in a restaurant.
He was acquitted of another charge of firing a gun in public, through the sunroof of a car, and of illegal possession of ammunition in the home where he killed Ms Steenkamp.
The parents of Reeva Steenkamp said "justice was not served" after Pistorius was acquitted of murder.
June and Barry Steenkamp told NBC News of their "disbelief" that the court had believed Pistorius's version of events.
Earlier, Arnold Pistorius, the athlete's uncle, said the family was "deeply grateful" to the judge for finding him not guilty of murder and that a "big burden" had been lifted.
South Africa's prosecuting authority said it was "disappointed" that Pistorius was not convicted of murder but said it would wait until after sentencing to decide whether to appeal.
Despite the conviction, the International Paralympic Committee has said Pistorius would be allowed to compete in future events.
Director of media and communications Craig Spence told BBC Radio 5 Live: "Oscar's done a great deal for the Paralympic movement. He's been an inspiration to millions, but obviously his priority now is to see what the judge decides.
"If he wishes to resume his athletics career then we wouldn't step in his way. We would allow him to compete again in the future."