A witness heard gunshots, screaming, and then more shots fired at the home of athlete Oscar Pistorius on the night Reeva Steenkamp was killed, a police officer has said.
Day two of his bail hearing in Pretoria also heard testosterone and needles were found in Mr Pistorius' bedroom.
He denies the premeditated murder of Ms Steenkamp, his girlfriend, saying he mistook her for an intruder.
A full trial of the Paralympic star, 26, is not expected for months.
However, allegations of what happened on Valentine's Day last week have continued to emerge in the packed courtroom.
Interest is at fever pitch, correspondents say, and courtroom proceedings were delayed as journalists and onlookers tried to get into the court. One journalist fainted in the scrum.
As the prosecution began setting out its case on Wednesday, it said a witness had testified to hearing "non-stop talking like fighting" between the hours of 02:00 and 03:00 on 14 February.
The first officer to arrive on the scene - chief investigating officer Hilton Botha - later said a witness had testified to hearing screams and gunshots from the house.
"We have statement of a person who said after he heard gunshots, he went to his balcony and saw the light was on. Then he heard a female screaming two-three times, then more gunshots," Mr Botha told the court, according to AFP news agency.
Mr Pistorius claims he was asleep until only moments before the shooting and that there was no argument between the couple.
Earlier, Mr Botha said he arrived at the house at 04:15 and found Ms Steenkamp lying dead on the ground floor. She was wearing white shorts and a black vest and was covered in towels, he said.
A lawyer and Mr Pistorius's brother were already at the scene.
Mr Botha said a memory stick was recovered with details of Mr Pistorius's offshore bank accounts - and claimed that made him a flight risk.
And he said Mr Pistorius would face an additional charge of possessing unlicensed ammunition.
Ms Steenkamp was shot in the right side of her head, her right hip and her right elbow, Mr Botha said.
He later testified that he thought the bullets were fired "down", suggesting Mr Pistorius had his prosthetic legs on.
Mr Pistorius has claimed he was walking on his stumps - making him feel particularly vulnerable - but the prosecution has argued he stopped to put his legs on, adding weight to its case that the shooting was premeditated.
Mr Botha said police found two boxes of the male sex hormone testosterone and needles in Mr Pistorius's bedroom.
But Mr Botha was later put on the defensive when questioned by Mr Pistorius's lawyer, says the BBC's Andrew Harding who is in the courtroom.
He admitted one witness who heard arguing at the house was in her own home 600m (a third of a mile) away.
The testosterone found was actually a legal herbal remedy used by athletes, the defence said.
It accused Mr Botha of putting the "worst possible interpretation" on the evidence.
On Tuesday, Mr Pistorius told the court he had woken in the middle of the night and heard what he thought was an intruder in the bathroom.
He shot through the door and only then realised Ms Steenkamp was not in bed.
He said he was "absolutely mortified" at her death.
The magistrate has deemed this a schedule six case - meaning Mr Pistorius is accused of premeditated murder.
His defence team will have to prove the extenuating circumstances that would justify granting bail.
Two days were set aside for this bail hearing, but it now looks as though it might not be completed until the end of the week, says the BBC's Peter Biles outside the court.
The first day of the hearing on Tuesday coincided with Ms Steenkamp's funeral.
The 29-year-old model and law graduate was cremated in her home town of Port Elizabeth.
Her father, Barry Steenkamp, told reporters: "We have to keep Reeva in our hearts forever."
The case has aroused huge interest both in South Africa, where Oscar Pistorius is regarded as a national hero, and around the world.
He is a multiple Paralympic champion, winning gold medals at the 2004 Games in Athens, at Beijing 2008 and at London 2012.
In London he made history by becoming the first double amputee to run in the Olympics, progressing to the semi-finals of the 400m.