The brother of murder suspect Oscar Pistorius has been acquitted of killing a woman.

Carl Pistorius, 28, had been accused of culpable homicide - or negligent killing - over the death of Marietjie Barnard on South in South Africa in March 2008.

Bu his trial collapsed when prosecution lawyers admitted at Vanderbijlpark Magistrates Court that they had been unable to prove the case against him.

The magistrate ruled that the defendant had not been negligent in her death. Postorius wept in court as he was cleared.

Prosecution spokesman Medupe Simasiku said: "We do accept the decision of the court and we will not be taking any further action on this case."

Barnard, 36, was killed when the motorbike she was riding hit Pistorius's pick-up truck. Lawyers for Pistorius claimed that Barnard was drunk at the time and intended to call two witnesses to say they smelled alcohol on Barnard at the scene of the collision.

But prosecution lawyers called a witness who testified that she had been drinking when they were working together - hours before she died.

Carl Pistorius was also cleared of driving in a reckless and inconsiderate manner.

The acquittal of Pistorius will come as a relief to his family as his brother, Paralympian Oscar Postorius, prepares for his trial charged with murdering girlfriend Reeva Steenkamp.

Fallen Olympic hero Pistorius is accused of murdering her on Valentine's Day with a gun he kept at his home in a gated community outside the capital of Pretoria.

He denies the charge, claiming he mistook her for an intruder on his property.

The athlete has withdrawn from all races this year.

His coach said he was not in a fit state to train properly under the pressures of the impending trial.