Alexander Jason in his popular video comparison of the noise made by a bat and a gun he filmed during the Oscar Pistorius trial
Alexander Jason in his popular video analysis of the noise made by a bat and a gun

A viral web video comparing the sound of gunfire with the noise Oscar Pistorius made hitting his bathroom door with a bat has been cited inside the courtroom at the runner's murder trial.

The clip showing a crime scene specialist in California analyse the noises, went viral after being uploaded to YouTube.

Lawyer Barry Roux mentioned the video during cross-examination on day nine of Pistorius's murder trial at North Gauteng High Court in Pretoria.

He asked police witness Lt Col Vermeulen if he had seen the video made by Alexander Jason. "I've not seen any police officer watch that video and I've not seen the video," Vermeulen replied.

In the footage, Alexander Jason set out to establish whether the two noises were distinguishable by setting up a microphone 180m away from him – the same distance as trial witnesses were from Pistorius's home when he killed Reeva Steenkamp.

At the trial, Roux appears to be pursuing a defence strategy to undermine State witnesses as he bids to get Pistorius off the murder charge.

Previously, the tough-talking lawyer got another witness to admit he had been following proceedings on Twitter. The lawyer – whom Pistorius is paying a rumoured £3,500 a day, told Darren Fresco it meant his testimony was "tailored" by what he had seen online.

In the video Jason struck a door with a bat and then fired four shots into the ground. He concluded the noises were sufficiently similar for witnesses to potentially confuse one sound with the other, from a distance 180m away.

Day nine of proceedings also featured disturbing images of Steenkamp's blood on Pistorius's prosthetic leg. The photograph was too much for her friend Desi Myers in the public gallery as she appeared to break down in tears.

The Olympian and Paralympian denies murdering girlfriend Steenkamp. He claims he thought she was an intruder in his luxury home on the outskirts of Pretoria. Pistorius also faces firearms charges.

The trial continues.

Reeva Steenkamp and Oscar Pistorius
Reeva Steenkamp and Oscar Pistorius had been dating for a few months before she was shot dead (Reuters)