Bizarre footage showing South African Olympian Oscar Pistorius re-enact the Valentine's Day 2013 slaying of his ex-girlfriend Reeva Steenkamp has emerged, New York Daily News reported, with the Seven Network defending its decision to air the program Sunday night on Australian television.

The video, aired on Seven's Sunday Night program, was obtained unlawfully by the network, lawyers for the Olympian have claimed, describing the decision to show it as a staggering breach of trust. However, Sunday Night executive producer Mark Llewellyn issued a statement Monday saying that the video would not have been televised if the channel had obtained the footage unlawfully.

"The material shown on Sunday Night goes to the heart of both the prosecution and defense cases, including the account provided by Oscar Pistorius," Llewellyn said "We would not have run the footage if we thought we had obtained it illegally. The story was run in Australia only and not made available to any other territory."

In the footage, the double-amputee Pistorius is seen standing in a corner without his prosthetics, wearing a sleeveless T-shirt and gym shorts while pointing his hand as if aiming a gun. Later, he is shown hurriedly putting on his prosthetics and then carrying a lifeless woman's body - first down a staircase, and then placing her on the ground.

The video was made by the Evidence Room, a U.S. company based in Cleveland, Ohio, that specializes in forensic animation, according to The Age. In October 2013, they were hired by the defense team to digitally depict the sequence of events early on Valentine's Day last year, when Pistorius shot his girlfriend four times through a locked toilet door.

Brian Webber, a lawyer representing Pistorius, said in a statement the video was "obtained illegally and in breach of the non-disclosure agreement with The Evidence Room."

"Channel Seven purchased this footage unlawfully," said Webber, adding that the broadcaster had agreed not to air the material until the end of the trial. "Whilst we cannot imagine how any of the footage would not support Oscar's version, we will only be in a position to comment further once we have had the opportunity to study what has been aired."

Pistorius, who is free on bail, faces 25 years to life in prison if found guilty of premeditated murder, but he could also be sentenced to a shorter prison term if convicted of murder without premeditation or negligent killing. Additionally, he faces separate gun-related charges. The high profile trial is fast reaching its end.