Prosecutors have challenged two of Oscar Pistorius' key claims about the night he shot and killed his girlfriend Reeva Steenkamp.
Investigating officer Hilton Botha said a witness saw lights on after the shooting - despite the Paralympian earlier claiming he was too frightened to switch on the light, fearing intruders were inside his home.
A statement on behalf of the 26-year-old athlete - which was read out in court on Tuesday - also said he was not wearing his prosthetic legs at the time and felt vulnerable.
But Mr Botha said the trajectory of the shots fired through the bathroom door was downward, suggesting Pistorius had been firing from a standing position and must have a been wearing the limbs.
The court was also told that "non-stop shouting" was heard coming from Pistorius' home before Miss Steenkamp was shot dead.
Prosecutor Gerrie Nel said a witness heard the shouting between 2am and 3am.
The details were revealed during Pistorius' ongoing bail hearing at Pretoria Magistrates' Court.
In an affidavit, Pistorius denied murdering the 29-year-old model at his home in the early hours of Thursday.
He said the couple were in love - and he fired through a closed toilet door within the bathroom, hitting the victim, thinking a burglar or burglars were inside.
Mr Botha described the moment he arrived at the athlete's house in the early hours of the morning and found Miss Steenkamp's body lying on the ground floor at the bottom of the stairs.
He said she was dressed in white shorts and a black top, and covered in towels.
The officer told the court that he saw a firearm on the shower mat, and one bullet case in the passageway and three in the bathroom.
He said unlicensed .38 calibre ammunition had been found at his home, and he wanted the Olympian charged with unlawful possession.
Mr Botha also told the court that needles and testosterone were also found in his bedroom.
But later Medupe Simasiku, the spokesman for the state prosecutor, said it was too early to say if the substance was testosterone as it was still undergoing laboratory tests.
The court heard that Mr Botha had previously arrested Pistorius for assault after a woman complained the athlete had assaulted her. The case was later dropped.
Later in the day Pistorius' lawyers launched a strong defence of the star , and Sky's Alex Crawford said it had been a good day for the defence.
Earlier the Paralympian arrived at the court in the back of a police car with a blue blanket covering his head. He entered the courtroom wearing a dark suit and tie just after 8am UK time.
The chances of Pistorius being given bail lessened at the first bail hearing on Tuesday after Magistrate Desmond Nair ruled the case a schedule six offence - meaning premeditated murder.
It means his lawyers now have to prove "exceptional circumstances" for him to be granted bail until he goes to trial.
Mr Botha told the court that Pistorius is a "flight risk" and could flee if given bail.
He admitted that he initially had no objections to Pistorius being given bail, but changed his mind after speaking to the forensics team.
He said the athlete has offshore accounts and a house in Italy, and stressed that South Africa did not have extradition agreements with all countries.
Pistorius has said he had been a victim of crime and received death threats, but the court heard there were no records of this.
His father Henke and brother Carl - who have supported him in the two previous hearings - looked on from the public gallery.
The proceedings were delayed as more than 100 journalists squeezed into court to report the hearing.
There were chaotic scenes as one reporter fainted, an overflow room was set up to provide more space and courtroom screens had technical problems.
The hearing was adjourned until Thursday, but one court official has speculated that it could run until Friday.