South Africa’s unfinished racial journey, thus, has been on trial as much as Mr. Pistorius or the legal system that seeks to bring justice to a tangled case.

That point was not lost among the many foreign observers of the trial. “It is an irony lost on no one that in a country with such a prominent history of racial tension, the world will be watching on Thursday as a black woman who grew up in the poor townships of South Africa sits in judgment of a white man of class, privilege and wealth,” wrote Lisa Davies in the Sydney Morning Herald.

If Mr. Pistorius, a Paralympic champion and Olympic sprinter, is found guilty of premeditated murder, he faces a mandatory life sentence with a minimum 25-year jail term before he is permitted to seek parole. But sentencing could be more complicated.

William Booth, a South African defense lawyer, told the Cape Town Press Club this month that there was “quite a significant risk” that Mr. Pistorius could be convicted of murdering the intruder he thought was in his home. Anyone firing into such a confined space must have known the risks, Mr. Booth said.

Mr. Nel has derided Mr. Pistorius’s version of events and accused him of lying and inconsistency in his defense.

State prosecutors, however, must prove Mr. Pistorius’s guilt beyond reasonable doubt, Mr. Booth said, and, if the judge accepted his version, other factors would weigh in the balance, such as his emotional state and South Africa’s high levels of violent crime.

Mr. Booth said an alternative charge of culpable homicide, carrying a lesser prison term and offering the judge greater discretion in sentencing, could also be considered. Since there are no jury trials in South Africa, Judge Masipa, assisted by two assessors, will decide the case. Some South African legal analysts said her summing-up of the testimony could run into Friday, delaying the pronouncement of the verdict.