Oscar Pistorius' defense rests in murder trial

Final stretch: Pistorius defense calls last w... 02:15

PRETORIA -- After 39 days in the courtroom spread over four months, and 37 witnesses on the stand, finally Oscar Pistorius' sensational murder trial is drawing to a close.

After calling 16 witnesses, Pistorius' defense team decided Tuesday it had done enough to prove that the double amputee track star mistook his girlfriend Reeva Steenkamp for an intruder early on Valentine's Day morning in 2013, and had no intention of killing her.

The defense rested its case, but it hasn't been an easy battle.

Their star witness -- the only person who knows exactly what happened that night -- was Oscar Pistorius. But he fell apart on the witness stand under relentless cross-examination by chief prosecutor Gerrie Nel.

Oscar Pistorius: Shots in the Dark 43:34

Nel showed no mercy as he forced Pistorius to confront graphic photographs of his Steenkamp's bullet-shattered skull. As Pistorius contradicted himself and forgot key parts of his own evidence, Nel accused him of lying, saying he was fumbling in an effort to recall a fabricated version of events.

The defense has had to counter prosecution evidence from neighbors who testified to hearing the blood-curdling screams of a terrified woman through their windows in the early morning hours.

The prosecution also brought ballistics experts to the stand, who told the court there was enough time between the shots fired by Pistorius for a woman to scream.

The defense's own forensic experts were largely decimated by Nel.

In the end, the defense relied on an argument that seems somewhat ironic, given Pistorius' superstar athletic status; that he has spent his whole life trying to prove that he is no different to able-bodied athletes. Now his future may depend on his lawyers' ability to emphasize the significance of his disability..

"I'm not disabled," Pistorius told a British journalist in 2005. "I just don't have any legs."

Psychologist: Oscar Pistorius a suicide risk 01:38

But over the past few days, the issue of the former Olympian and Paralympian's disability took center stage in the Pretoria courtroom, and a key pillar of his defense will be, as one local commentator put it, "the psychology of vulnerability that accompanies his disability."

The defense has portrayed him as a completely vulnerable man, when not wearing his prosthetic legs.

Events outside the courtroom, however, provided a sharp contrast to this argument. Damning video was leaked of Pistorius re-enacting the shooting -- on his stumps.

The defense commissioned the video from U.S.-based forensic animation company "The Evidence Room," but never used it in court.

It was leaked to an Australian television network, and shows Pistorius moving backwards and forwards on his stumps re-enacting the events leading up to his killing of Steenkamp.

But while the video made global headlines, it had no impact on the case as it was never shown inside the courtroom.

Both sides will spend the next month preparing their final arguments, and a verdict is expected before the end of August. The decision rests in the hands of the judge alone, as there is no jury system in South Africa.