Model, actress and radio personality Pearl Thusi was in a car accident that left her and her daughte.
"We say that the degree of violence present in this case is horrific," Nel said in the Pretoria Magistrate's Court as he opposed the granting of bail for Pistorius.
Pistorius is charged with the murder of Steenkamp after she was shot dead in a toilet in his home. He has not pleaded but said in an affidavit he thought there was an intruder in the house when he fired into the toilet cubicle.
Nel said that the court should not do "lip service" to reduce crime against women.
"Even the president said in his State of the Nation address we should prioritise violence against women," said Nel.
He mentioned the recent gang rape and murder of Western Cape teenager Anene Booysen. This was in response to Magistrate Desmond Nair asking Nel to give evidence on violence.
Nel said the court must know how many cases of murdered women were on its roll.
Being in the toilet cubicle must have been "horrific... having four shots fired in," said Nel, as Pistorius cried while he spoke.
Nel said there was a lot of interest in the case, with Women, Children and People with Disabilities Minister Lulu Xingwana also attending the hearing.
"He has been protected too much. Now there is a person dead."
Nel was referring to friends covering up for Pistorius after he had threatened someone.