Setback for prosecution in Pistorius' Steenkamp shooting case

South African prosecutors have removed a key argument for premeditation by reportedly admitting that Paralympic sprinter Oscar Pistorius may not have been wearing his prostheses when he fired the shots that killed his girlfriend, model Reeva Steenkamp.

Pistorius, who goes on trial March 3, denies the charge of murder and says he mistook Steenkamp for an intruder.

According to the Sydney Morning Herald, leaked documents claim the state's own ballistics expert believes that the Blade Runner was 'most likely' on his stumps when he shot Steenkamp through the bathroom door, dismissing the prosecutors' argument that Pistorius took time to put on his prosthetic legs before firing the shots.

The documents also claimed that the prosecutors believe security guards at Pistorius' gated community called the Olympian after the shooting to see if everything was OK, and that he said it was fine and did not require assistance, adding that they also believe a neighbour heard shouting on that fateful night.

However, the National Prosecuting Authority said it had not leaked the documents, the report added.