If Masipa does not believe the athlete thought there was an intruder, she will find him guilty of murder and sentence him to a prison term ranging from 15 years to life. South Africa does not have the death penalty.
If Masipa accepts that Pistorius did not know that Steenkamp was the person he was shooting at, she could find him guilty of culpable homicide, a lesser charge than murder, or acquit him, according to CNN analyst Phelps.
A verdict of culpable homicide would leave the sentence at Masipa's discretion.
The trial is scheduled to continue Monday for a 38th day.