After six months of evidence centred on Pistorius and last year's Valentine's Day shooting, Steenkamp's family had their day in court, painting a picture of a thoughtful, caring young woman whose death felt like "the end of the world."
Acting as a witness for the prosecution, Steenkamp's cousin Kim Martin gave heartfelt evidence about the slain model's journey from "fun-loving child" to victim of a tragedy that "ruined our whole family".
Pistorius, 27, was found guilty last month of culpable homicide over the killing of the 29-year-old law graduate, but was acquitted of murder.
In today's sentencing hearing, Nel warned that justice itself was on trial and that if the star sprinter was seen to go free, South Africans would lose confidence in the legal system.
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Slamming the defence's suggestion of community service "shockingly inappropriate," Nel warned that "if the court sentence is too light, and society loses trust in the court, they will take the law into their own hands."
Nel today sought to tip the scales of justice by putting the former model and reality TV star centre stage.
"I must be Reeva's voice," the cousin said, breaking down on the stand as she explained that Steenkamp's parents had encouraged her to speak on behalf of their daughter.
"I had to do this for Reeva, I owe it to her."
She recalled Reeva was the first baby she ever held, and recounted a joyful shared childhood filled with horse-riding, school homework and time with family.
As Martin recounted her cherished memories, Steenkamp's father Barry, who suffered a near-fatal stroke after Reeva's death, wept in court, his shoulders shaking.