June Steenkamp, the mother of model Reeva Steenkamp, who was killed by Pistorius, arrived at the courthouse dressed in black and looking somber.
She was quoted in the Pretoria News saying that she wants to see Pistorius as he enters the courtroom for his murder trial.
"I want to look at Oscar, really look him in the eyes, and see for myself the truth about what he did to Reeva" said June Steenkamp, 67.
We love Oscar, and believe in him, and will be standing by him throughout the coming trial.
"Whatever the court decides at the end of his trial, I will be ready to forgive him ... But first I want to force him to look at me, Reeva's mother, and see the pain and anguish he has inflicted on me. I feel I need that."
Steenkamp's mother was seated on the same bench in court as Pistorius' family, and behind and to the right of where Pistorius was due to sit, so there is a possibility that their eyes will meet immediately.
A drone carrying cameras flew over the entrance to the courthouse to capture the scene as under grey, drizzly skies, family members, journalists and lawyers arrived.
The intense public interest in the Pistorius trial is shown by the launching on Sunday night of a 24-hour cable channel devoted to covering the court case.
The start of the trial marks the start of a dramatic new chapter in the life of the double-amputee athlete who ran at the Olympics and became a global star before he shot his girlfriend to death.
Prosecutors charged the 27-year-old Pistorius with murder in Steenkamp's death and say it was with premeditation.
They say they will seek a life sentence if Pistorius is convicted, the sternest punishment available in South Africa. South Africa no longer has the death penalty.
If convicted on the murder charge, Pistorius could be sent to prison for at least 25 years before the chance of parole, the minimum time someone must serve if given a life sentence in South Africa.
The state says Pistorius intentionally killed Steenkamp at his home in the pre-dawn hours of Valentine's Day last year by shooting her through a toilet door after an argument.
Pistorius denies murder and says he killed his girlfriend by mistake when he fired four times through the door thinking there was a dangerous nightlife intruder on the other side.
A lesser sentence is possible if Pistorius is found guilty of murder but without premeditation.
He also could be convicted of culpable homicide, South Africa's version of manslaughter in which someone is killed through negligence.
Pistorius claims he was acting in self-defense against what he believed at the time was a threat to his life.
As well as murder, Pistorius faces a second charge of illegal possession of ammunition for bullets found at his Pretoria house that he allegedly didn't have proper licensing for.
More gun charges
Prosecutors say he also will be indicted on Monday with two more gun charges relating to him allegedly shooting in public on two separate occasions before Steenkamp's killing.
The serving of an updated indictment to Pistorius in court is expected to be the first move at the trial at Pretoria's high court.
The gun charges reportedly relate to him allegedly shooting out the sunroof of a car in one incident and another when he allegedly fired a gun inside a restaurant, apparently by mistake.
Those incidents happened in the court jurisdiction of the city of Johannesburg, not where Steenkamp was killed in Pretoria, and prosecutors applied to have the two charges included and heard at his murder trial.
Female judge Thokozile Masipa will ultimately pronounce the champion runner innocent or guilty and will decide on any sentence. South Africa has no trial by jury.
Parts of the trial will be broadcast on live television, both in South Africa and across the world, and hundreds of reporters are expected to descend on North Gauteng High Court in the South African capital for the start of the trial.
Pistorius says his fear of crime was why he fired four shots through the door, hitting Steenkamp three times - in the head, elbow and hip.
Prosecutors maintain he was simply angry with her after an argument.
His uncle, Arnold Pistorius, sister Aimee and brother Carl are all also listed as state witnesses.
"We love Oscar, and believe in him, and will be standing by him throughout the coming trial" Arnold Pistorius said in a statement over the weekend.
The presence of Steenkamp's mother is the first time that any members of the victim's family have attended any of Pistorius' previous court appearances.