Carl Pistorius.
Pistorius was acquitted on a charge of culpable homicide by the Vanderbijlpark Magistrate's Court on Tuesday.
National Prosecuting Authority (NPA) spokesperson Medupe Simasiku said the state failed to prove a watertight case against him.
"We do accept the decision of the court and we will not be taking any further action on this case moving forward," Simasiku said shortly after the judgment.
Pistorius was facing a culpable homicide charge after an accident in 2008 that led to the death of a 36-year-old woman.
Blood tests conducted by the police at the time proved that he was not under the influence of alcohol at the time.
Charges withdrawn
The state later withdrew the charges against Pistorius, but the NPA had them reinstated.
Carl's appearance at the Vanderbijlpark Magistrate's Court on culpable homicide charges on March 27 came a day before Oscar challenged the bail conditions the Pretoria Magistrate's Court imposed on him.
Double amputee Oscar Pistorius, known as the "Blade Runner" for his trademark artificial limbs, is accused of murdering his girlfriend, Reeva Steenkamp on Valentine's Day. – Sapa