Oscar Pistorius's defence is seeking to prove that a married couple who heard screams on the night of Reeva Steenkamp's death colluded in their testimony.
Pistorius's lawyer Barry Roux attempted on Wednesday to show written statements and testimony from husband and wife couple Charl Johnson and Michelle Burger contained "remarkable coincidences" that could not be accidental.
Earlier, in vivid testimony that cast doubt on the Paralympian's claims of a "tragic accident," the pair told the court they heard screams then gunshots on Valentine's Day 2013 at Pistorius's home.
The couple's account would undermine Pistorius's claim that he shot his girlfriend, a 29-year-old model and law graduate, through a locked toilet door after mistaking her for an intruder.
As the trial resumed on Wednesday, Roux sought to put the defence back on the front foot, submitting Johnson to pointed cross-examination a day after his wife was reduced to tears in the witness box.
"You have not favoured the court with a strong, independent version," he railed at Johnson, citing identical syntax and vocabulary used in Johnson and his wife's written statements to police.
The allegation could lessen the impact of the pair's testimony.
"Maybe you and your wife should have stood together in the witness box," Roux said, prompting Judge Thokozile Masipa to step in.
"Aren't you going a bit far?" she asked.
Masipa did not comment on Johnson's complaint that his "privacy has been compromised severely" by the reading in court of his mobile phone number, and that he had received threatening messages.
Johnson earlier told the court that on February 14, 2013 he was woken by a woman's screams and ran to his balcony, less than 200 metres from Pistorius's home.
"At that point the fear and intensity of her voice escalated and it was clear that this person's life was in danger," he said on Tuesday.
"That's when the first shots were fired," although Johnson could not recall how many.
On Tuesday the court heard emotional evidence from Burger about her recollection of that event.
"When I'm in the shower, I relive her shouts. The terrifying screams," university lecturer Burger said, her voice cracking with emotion as she was unable to hold back the tears.
Another neighbour, second witness Estelle van der Merwe, who lives less than 100 metres (yards) away from Pistorius's home, also told the court she heard arguing coming from the house.
"I woke up in the morning at 1:56am to sounds of someone talking loudly and fighting," she told the court. "It lasted about an hour."
Later she recalled waking up to the sound of loud bangs.
Pistorius, 27, a double amputee known as the "Blade Runner" for his carbon-fibre running blades, has pleaded not guilty to murder and three unrelated gun charges.
If found guilty of premeditated murder, Pistorius faces 25 years in South Africa's notoriously brutal jails and an abrupt end to his glittering sporting career.
The track star has appeared composed in court during three days of prosecution testimony, except when the court heard a statement explaining the violent nature of Steenkamp's death.
Seeking to cast doubt on the witnesses' statements, the defence has disputed their claims they continued to hear Steenkamp's fading screams after she suffered a final shot to the head.
