Shafeeka Baartman was found with a scarf around her neck, and her legs tied with clothing at a house on Friday night, said Captain Bernadine Steyn.
Earlier in the day, the girl was sent by her mother to a friend’s house to fetch money, according to police.
“On her way to the house [a] suspect approached her on foot and took her to his house… where he allegedly raped and murdered her,” said Steyn.
A 31-year-old man was arrested on a farm outside Uniondale on Saturday in connection with the crime.
He is due to appear in the Uniondale Magistrate’s Court on Monday.
A post mortem would be carried out on Sunday afternoon in Oudtshoorn, said Steyn.