You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
Wielding the cricket bat in his hands, police colonel Johannes Vermeulen knelt down before swinging it at the wooden door in a court reconstruction to show the angle of the marks and to suggest they could only have been made by someone much shorter than him.
The 27-year-old track star is charged with the murder of model and law graduate Reeva Steenkamp, whom he shot through the locked toilet door on Valentine's Day last year.
Prosecutors want to prove that it was premeditated killing, but Pistorius says he was defending himself from what he thought was an intruder who had broken into his gated-community home in the capital of the crime-ridden country.
At his bail hearing last year, Pistorius justified shooting because of the extreme vulnerability he felt because of his disability. However, in his affidavit he stated that he had put on his prostheses before smashing down the door.
"The marks on the door are actually consistent with him not having his legs on and I suspect they must be similar to the height that he was when he fired the shots," he told the court.
Defence advocate Barry Roux countered by suggesting that even with his legs on, Pistorius would not be swinging a bat at the same height as an able-bodied person.
Close-up photographs of the damaged door were shown in court, as well as scuffs on the bat autographed by South African test cricketer Herschelle Gibbs.
Lead defence lawyer Roux later heaped scorn on the state's evidence, again accusing police of shoddy detective work, after Vermeulen testified that police reassembled the broken door with a temporary adhesive.
"The door was brought up from the bathroom in a body bag. The panels were loose," the police colonel testified, adding he received both the door and the cricket bat in materially different condition from how they were found at the scene.
Vermeulen also said he did know where the door had been kept immediately after it was removed from Pistorius' house.
Roux countered that door was marred by "serious marks" while with forensics. Pistorius' defence has looking to sow doubt about the quality of the police work in the case, particularly around its handling of evidence.
At last year's bail hearing, Roux dismantled the lead detective on the case, Hilton Botha, accusing him and contaminating the crime scene.
Botha, who backtracked on details such as the distance of witnesses from Pistorius' home, was later pulled off the case when it emerged he was facing seven attempted murder charges for opening fire on a minibus full of passengers.
Pistorius' lower limbs were amputated as a baby but he overcame the disability to become the "fastest man on no legs", winning gold medals at both the Beijing and London Paralympics.
With good looks and an easy smile, he was a sponsors' dream, but since Steenkamp's killing the accounts of his behaviour have revealed a dark side to his carefully groomed media persona.
Prosecutors are trying to show Pistorius loved the fast life, with an unhealthy obsession for guns.
Darren Fresco, a friend, earlier told the court Pistorius had been driving at above 200 kph when the pair and one of the athlete's ex-girlfriends were travelling to a resort town south of Johannesburg in September 2012.
Pistorius' gun lay between his legs and not in a holster when the three drove back later that day, Fresco said.
Both Fresco and Samantha Taylor, the woman Pistorius left for Steenkamp, have testified that the athlete shot through the car's sunroof in anger when a policeman emptied the magazine of Pistorius' firearm, after they were pulled over for speeding.