The South African athlete Oscar Pistorius did not have his prosthesis on when he broke the bathroom door where his girlfriend was at the time of her death, according to testimony given Wednesday by the young forensic expert .

The defense claims that Pistorius smashed the door after realizing he had shot his girlfriend, model Reeva Steenkamp. Prosecutors, meanwhil , say the athlete destroyed the bathroom door to shoot .

In a preliminary testimony, the athlete said he had put on his prosthesis and had acted under the vulnerability he felt by his disability .

The scene was rebuilt in the audience – with a model of the bathroom stall door and bat – with assistance by the forensic expert, Gerhard Vermeulen .

The time between shots and the damage to the door is considered crucial to the case .

Pistorius, the first disabled athlete to compete in the Olympics, caused the death of his girlfriend in February 2013 after shooting him several times.

The athlete maintains that he mistook Steenkamp for a burglar who had entered his home, while the prosecution claims it was a premeditated act.