Reeva's uncle, Michael Steenkamp, broke down in tears when describing to reporters what a close-knit family she belonged to and how all of her relatives had been due to celebrate Christmas together.
He said that Reeva had spoken about her desire to become an activist fighting abuse against women in the months before her death.
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Ricardo Medina is charged with stabbing his flatmate to death with a sword.
Police are hunting a man who is suspected of grabbing an 11-year-old girl who only got away by biting her attacker's hand.
The storm is expected to hit the country's southern coast on Monday.