A forensics expert on Wednesday staged a dramatic re-enactment of how Paralympian Oscar Pistorius broke down the door of the toilet where he shot dead his girlfriend.
Police Colonel Gerhard Vermeulen brought before the South African court both the door and the cricket bat -- two pieces of physical evidence which could hold the key to the case.
In opening testimony Vermeulen demonstrated how the door was struck with the bat, which was in turn used to wedge open a gap between a panel and the inner frame.
"The bat went through the door and there's actually marks on the tip of the bat which correspond with what happened," said Vermuelen, a forensics expert with three decades of experience.
"The person kind of twisted the bat to break open the door."
The sequencing of gun shots and the damage caused by the bat is crucial to both prosecution and defence account of events on February 14, 2013.
Pistorius says he mistakenly shot his girlfriend Reeva Steenkamp through the locked dark wood door four times, believing she was an intruder, then realising his mistake broke it down with a cricket bat.
The prosecution says Pistorius first hit the door with a bat in an effort to get to Reeva Steenkamp, then shot through the door.
Vermeulen did not give details about the sequencing, but demonstrated that height measurements showed that Pistorius was not wearing his prostheses at the time he struck the door.
The gold medallist claims he had his prostheses at the time having put them on in an attempt to first kick the door down.
During eight days of testimony the prosecution has already called upon witnesses who have testified hearing arguing, screaming and gunshots coming from Pistorius's house.
A pathologist who conducted Steenkamp's post-mortem report has also testified, but did not detail the exact sequence of events on the fateful night.
He testified that Pistorius shot Steenkamp, a 29-year-old model and law graduate, with "Black Talon" ammunition, hollow-point bullets which mushroom open like a jagged flower on contact to cause maximum tissue damage.