An appeals court overruled Masipa, the trial judge, and determined that Pistorius was guilty of murder, exposing Pistorius to the stiffer sentence.
Many observers expected a sentence of between 10 and 15 years, with credit for time already served.
South Africa has some of the world’s highest rates of violent crime, and many home owners have weapons to defend themselves against intruders, although Pistorius’s complex is surrounded by a three-meter high wall and electric fence.
In 2004, Springbok rugby player Rudi Visagie shot dead his 19-year-old daughter after he mistakenly thought she was a robber trying to steal his car in the middle of the night.
“It is difficult to imagine an intruder entering this community, but we live in a country where intruders can get in wherever they want to,” said one Silverlakes resident, who did not want to be named.