Paralympic champion Oscar Pistorius began sobbing in court today while an eighth witness gave evidence in the athlete's trial for alleged murder.

The 27-year-old has been accused of murdering his girlfriend Reeva Steenkamp, whom he shot dead through a bathroom door at his home in Pretoria, on Valentine's Day last year.

On day four of the trial, Johan Stipp, who lives in the Silverwoods Country Estate, which is the same complex as Pistorius's home where the murder occurred, took to the stand.

Mr Stipp told the court that he was awoken by three loud bangs in the early hours of February 14, 2013, and heard screaming that sounded "like the voice of a female".

The court heard how the witness approached Pistorius's home after calling security and saw a man on his knees next to a woman lying on her left side on the ground.

Mr Stipp, who lives 72 metres away from the sportsman's home, claimed while giving evidence that he heard Pistorius say: "I shot her. I thought she was a burglar and I shot her."

The South African athlete leaned forward and placed both hands on the back of his head and sobbed while Mr Stipp described how Steenkamp could not be revived, and that, at the time, Pistorius was crying, praying to God to keep her alive.

Pistorius has pleaded not guilty to murder.