Olympic and Paralympic star Oscar Pistorius is due to appear in court on Friday after being arrested on suspicion of murdering his girlfriend after she was shot dead at his home.
Gold-medal winner Pistorius, known as Blade Runner for his prosthetic racing legs, was taken into custody on Thursday morning over the killing of Reeva Steenkamp.
The 30-year-old was shot in the head and upper body.
As Pistorius was detained for questioning, police said there had been previous incidents of a "domestic nature" at the property on the exclusive, gated Silver Lakes Golf Estate in the South African capital Pretoria.
Initial reports suggested the model may have been mistaken for a burglar, but Brigadier Denise Beukes later said police were "very surprised" by that suggestion, adding: "These allegations did not come from us."
Brig Beukes said there was no sign of forced entry at the house. She said: "I can't confirm that it's related to the person that's arrested but I can confirm there has previously been incidents at the home of Mr Oscar Pistorius."
Police spokeswoman Lieutenant Colonel Katlego Mogale told the South African Press Association: "Paramedics declared the woman dead on the scene and police proceeded with their investigation. The woman sustained wounds to her head and the upper body."
A 9mm pistol was recovered. According to unconfirmed reports, four shots were fired.
Police said an application for bail by Pistorius's lawyer Kenny Oldwage would be opposed when he appears in court.
Just three days ago, Pistorius tweeted his excitement about his first race of 2013, accompanied by a photograph of him in action. He said: "1 month till my first race of 2013.. Can't wait to burn it up!"