Oscar Pistorius will be charged with the premeditated murder of girlfriend Reeva Steenkamp at his bail hearing at Pretoria Magistrate's Court.
After hearing both sides debate whether or not the shooting was premeditated, the judge, Desmond Nair, said: "I cannot at this point completely exclude planning."
Nair said that a premeditated offence did not necessarily have to have been planned for days or months before an event.
Suspects charged with premeditated murder rarely receive bail, and Pistorius's legal team will have to prove "exceptional circumstances" to save their client from incarceration.
Both defence and prosecution lawyers agreed that Pistorius shot Steenkamp through his bathroom door before breaking it down. They differed, however, on the cause and order of events.
Gerrie Nel, prosecuting, claimed that Pistorius had to put on his prosthetic legs, arm himself and cross his bedroom to the bathroom door before opening fire - suggesting the athlete had time to think about his actions.
Nel also asserted that Steenkamp had arrived at Pistorius's house nine hours before the shooting and had planned to stay overnight.
Even if Pistorius did think Steenkamp was a burglar, Nel said, the offence was premeditated given the defendant had plenty of time to consider whether or not to shoot. Furthermore, he asked why a burglar would lock themselves in a toilet while carrying out a robbery.
Pistorius's lawyer, Barry Roux, said it was common for burglars to lock themselves in toilets while hiding in other people's houses, and said that, by Nel's logic, anyone who shoots a burglar in the heat of the moment is guilty of premeditated murder.
The offence was "not even murder", Roux said, adding that Pistorius broke down the door after shouting when he realised his girlfriend was inside.