A chilling new video has leaked showing Oscar Pistorius re-enacting the sequence of events that occurred on the night he fatally shot his girlfriend.

On Sunday, Australian broadcaster Channel Seven aired exclusive video footage of the 27-year-old Paralympic winner without his signature prosthetic legs in a re-enactment of the night he killed his 29-year-old girlfriend, Reeva Steenkamp.

Pistorius was the first amputee to compete as an Olympic track athlete after he was selected to represent South Africa in the 2012 London Summer Olympics. However, his life took a sharp turn when he fatally shot Steenkamp on Feb. 14, 2013. The South African track star has pleaded not guilty to first degree murder, arguing that he shot her by mistake because he thought she was an intruder. Prosecutors, however, say he killed her after the couple had a heated argument in the wee hours of Valentine's Day.

Prosecutors asserted Monday that they "have nothing to do" with the leaked footage. They also indicated that they do not plan to extend the trial to introduce the video as evidence, according to ABC News. The video has not been shown in court, and it is not known how a television network got it.

The video appears to have been recorded at the sprinter's uncle's house. It shows Pistorius walking on his stumps while pretending to hold a gun. He is also seen picking up and carrying his sister, who appears in the video as a body double for Steenkamp.

During the trial, Pistorius' defense team has argued that the "Blade Runner" felt vulnerable to a possible intruder because he was not wearing his prosthetic legs at the time and had limited mobility. However, the video shows him with more mobility than the defense team described.

The Paralympian's family denounced the broadcaster's decision to air the video, which was produced by the defense team during its trial preparations, as a "staggering breach of trust," the Washington Post reported.

Pistorius "faces 25 years to life in prison if found guilty of premeditated murder," according to The Associated Press. He is currently free on bail.