Steenkamp's father broke down in court on Tuesday as he said Pistorius must "pay for his crime" of shooting his daughter three years ago.
It was the first time that 73-year-old Barry Steenkamp had testified in court and directly addressed the double-amputee Olympic sprinter.
Pistorius killed Reeva Steenkamp in the early hours of Valentine's Day in 2013, saying he mistook her for a burglar when he fired four times through the door of his bedroom toilet.
"It has been very difficult for me to forgive... I feel that Oscar has to pay for what he did. He has to pay for his crime," Barry Steenkamp said, tears streaming down his face.
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Reliving how his daughter, 29, died, Steenkamp said: "What she must have gone through in those split seconds -- she must have been in so much fear and pain."
Pistorius held his head in his hands and sobbed during the testimony on Tuesday in the High Court in Pretoria, the South African capital.
"June grieves like I do, all the time. I hear her at night, I hear her crying, I hear her talking to Reeva," he added, saying that June had tried to forgive Pistorius to help her cope with the loss of her daughter.
The identity of the final state witness to appear was not known.
The original trial judge Thokozile Masipa is due to hand down a new sentence for murder after arguments from both prosecution and defence are completed by the end of Wednesday.
The minimum jail term for murder is 15 years, but his sentence may be reduced due to time already spent in prison and mitigating factors, including his disability.
Pistorius was released from jail last October to live under house arrest at his uncle's mansion in Pretoria after serving one year of his five-year sentence for culpable homicide.
Yesterday, prison nurse Charlotte Mashabane, told the court that Pistorius had been a difficult inmate and had argued with officials, shouting and banging her desk in a dispute over medication.
Pistorius has always denied killing Steenkamp in a rage and, during his seven-month trial in 2014, vomited in the dock as details of his lover's death were examined in excruciating detail.
The year before he killed Steenkamp, Pistorius became the first double-amputee to race at Olympic level when he appeared at the London 2012 games.