The "petrified" screams, the state believes, testify to the horror Reeva Steenkamp endured in her final "agonising" moments.
Throughout the first day of his murder trial yesterday in the Pretoria High Court, Oscar Pistorius refused to acknowledge Steenkamp's presence, looking away or down when he walked past her as he entered or left the dock.
Reeva Steenkamp was shot in Pistorius's Pretoria home on StValentine's Day last year.
Pistorius maintains that he mistook her for an intruder.
The state claims that he killed her deliberately after an argument.
Prosecutor Gerrie Nel opened the state's case with witness Michelle Burger, a resident of Silver Stream Estate, which borders on Pistorius's Silver Woods Estate.
She described how she was woken by a woman's "petrified" screams.
"They were blood-curdling, hysterical. I was in bed. My husband ran to the balcony.
"You could hear the screams. Repeated, over and over again. The screams were for help. They were terrible, filled with fear.
"I then heard a man screaming for help, three times."
Burger said that she phoned the estate's security service; the woman was continuing to scream.
Four gunshots then rang out, with the screams "fading" seconds later.
"It was screams and then bang. Bang, bang, bang. That was it. We thought it was a burglary. I hoped the woman had not [had to watch] her husband die."
Pistorius's lawyer, Barry Roux, tried to rattle Burger by questioning her version of events and casting doubt on her ability to differentiate between the sounds of gunshots and the impact of the cricket bat Pistorius used to smash open the locked toilet door, and a lover's scream.
"Could you be wrong? Could your understanding be incorrect? Do you think you heard one thing but it was actually something else?" Roux asked.
"We have witnesses who will testify that Pistorius, if really anxious, can pitch his voice, sounding like a woman."
But Burger was adamant.
"I know what I heard and I am sticking to that. I heard screams - petrified, fearful - a man's yells for help, gunshots and then a fading voice."
Outside the court, a friend of the Steenkamp family said Burger's testimony made it "feel like Reeva Steenkamp is here in the room".
"You can hear her. You close your eyes . you see her.
"You hear her voice, her desperate screams.
"You can imagine her calling . calling for anyone, her mother, her father . for help."
"For June [Reeva's mother], it is killing [sic], but she has to be here. She needs the closure. No matter how painful, she needs to hear this - to see the man who took away her daughter, her Reeva."
She said Pistorius's lack of emotion was difficult to bear.
"There is nothing. Nothing, except the twitch above his eye. It's as though he is dead inside."
In addition to murder, Pistorius is facing three charges related to discharging a firearm and illegal possession of ammunition.
In his plea explanation, Pistorius conceded that he did not have a licence to possess .38 calibre bullets.
But that was the only concession.
He is sticking to his story that he mistook Reeva for an intruder.
"My discharge of the firearm was prompted by a sound I heard in the bathroom that led me to believe, in my fearful state and on my stumps, that a burglar had come to harm me and Reeva," he said.
Pistorius, who will take the stand in his defence, accused the state of trying to "introduce inadmissible character evidence" to prove that he and Reeva had argued.
Accused tweaks his story
Oscaar Pistorius's account of the events of the night on which he killed Reeva Steenkamp, given at his bail hearing, differs from his plea explanation yesterday.