Oscar Pistorius' father, brother and sister were among members of his family in court for the start of his bail hearing on Tuesday (February 19).
In opening statements, the prosecution claimed that Pistorius put on his artificial legs and walked across his bedroom before firing four handgun rounds into the locked bathroom door, killing Steenkamp in cold blood.
Pistorius wept uncontrollably in court as Nel outlined details of the shooting in the early hours of Thursday.
"If I arm myself, walk a distance and murder a person, that is premeditated," he said. "The door is closed. There is no doubt. I walk seven metres and I kill."