Oscar Pistorius's bail application in the Pretoria Magistrate's Court has been postponed to Friday for further argument.
The court heard prosecutor Gerrie Nel submitting on Thursday it wasn't a coincidence that the people who gave statements following Reeva Steenkamps death said they heard screams and arguments.
Nel asked why Pistorius didn't see that his girlfriend Reeva Steenkamp was not in bed when he reached for his firearm.
"There's only two people in the house and you want to protect her, but you don't even look at her?" asked Nel.
Pistorius is charged with the murder of Steenkamp, who died in a shooting in his Pretoria home last week.
He has denied shooting her deliberately, saying he thought there was a burglar when he fired shots at the bathroom door, killing her.
Nel said: "I'm just saying that his version is so improbable ... "
Even with Pistorius' version, there was no imminent danger in the bathroom.
Pistorius had said that there had been threats on his life and to his security at home, but he had never opened a case with the police.
"He was keen to arm himself and get to the intruder; his action is indicative of a man ready to arm himself, and ready to kill."
He said one could not create a danger and then act in self-defence.
It was "improbable" that Pistorius felt vulnerable, but still headed for the bathroom door, Nel said.
"It is our respectful submission that he fired four shots, not one shot. The only reason you fire four shots is to kill."
Nel continued: "At the least there will be culpable homicide."
He said it was also not disputed that Pistorius discharged a gun at Tashas restaurant in Johannesburg and "somebody else took the blame".
"That is the real person we are dealing with here," said Nel.
Nel was arguing there were no exceptional circumstances for Magistrate Desmond Nair to grant Pistorius bail.
Referring to a threat Pistorius made about "breaking someone's legs" he said: "What else are threats and a murder but prone to violence?"
Later on Thursday, Warrant Officer Hilton Botha was removed as lead investigator from the case.
National police commissioner Riah Phiyega said on Thursday the Pistorius investigation would now be handled by a team led by Divisional Commissioner of Detective services, Lieutenant General Vineshkumar Moonoo.
The bail application will continue at 10am on Friday. – Sapa