Oscar Pistorius' three-day cross-examination reached a dramatic climax on Friday when a prosecutor challenged the double-amputee sprinter repeatedly as to why his girlfriend failed to scream when she was shot four times through a toilet door.
In an electric exchange in the Pretoria High Court, Gerrie Nel, one of South Africa's top attorneys, said it was beyond belief that 29-year-old law graduate and model Reeva Steenkamp would have remained silent in the tiny cubicle with an armed Pistorius shouting and screaming in the adjoining bathroom.
Pistorius, who says he fired at what he thought was an intruder, said Steenkamp did not scream at any point in the incident in the early hours of February 14, 2013 - a central pillar of his defence.
However, under withering questioning, the 27-year-old track star was forced to concede that he may not have heard her cries because of his ears ringing from the first shot.
Several people living nearby have testified to hearing a woman's terrified screams before and during a volley of shots.
"She's awake. She's in the toilet. You're shouting. You're screaming. You're three metres from her. She would have responded. She would not have been quiet, Mr Pistorius," Nel said.
"She didn't respond, my Lady," a clearly distressed Pistorius replied, addressing judge Thokozile Masipa.
"Did she scream at all whilst you shot her four times?" Nel continued.
"No, my Lady."
"Are you sure? Are you sure, Mr Pistorius, that Reeva did not scream after the first shot?" Nel continued. "Are you, Mr Pistorius?"
After a brief silence to collect himself, Pistorius said: "My Lady, I wish she had let me know she was there."
"After you fired the first shot, did she scream?" Nel asked.
"No, my Lady."
"Are you sure? Would you have heard her?" Nel asked.
"I don't think I would have heard her."
"A gunshot went off, my ears were ringing," Pistorius said.
"How can you exclude the fact she was screaming if you couldn't hear?" Nel asked.
"If I couldn't hear it then I couldn't hear," Pistorius retorted.
"No, you said, Mr Pistorius, she never screamed. You couldn't hear. You're just saying that," Nel said.
"That is what I'm saying," Pistorius replied.
"No, that's not what you're saying. You're saying she didn't scream," Nel followed up.
"My Lady, the sound of that gunshot in the bathroom, you wouldn't have heard anyone scream. The decibels of the gunshot, I don't believe you would have heard anyone scream. When I had finished firing the gunshots, I was screaming and I couldn't hear my own voice."
Nel later followed up with his central accusation - that the couple had an argument and Steenkamp fled to the toilet pursued by Pistorius, who then shot her through the closed wooden door.
"You knew that Reeva went behind the door and you shot at her," Nel said. "You shot at her knowing she was behind the door."
Pistorius denied it, his voice wavering with emotion, before the court adjourned until Monday morning.
Pistorius faces life in prison if convicted of murder.