Former president Jacob Zuma’s son, Duduzane Zuma, is in the dock on Tuesday in his culpable homicide trial relating to the 2014 death of Phumzile Dube, 30, when his Porsche collided with a minibus taxi.

He heard on Tuesday that he will not have to answer for the death of Jeanette Mashaba, who died in hospital a few weeks after the crash on the M1 South highway near the Grayston Drive offramp.

The Randburg court heard that the state had consulted with a pathologist and Mashaba’s death was ruled a result of natural causes.

State prosecutor Yusuf Baba told the court that Mashaba suffered from a pre-existing condition, which the state was unaware of earlier, that led to her death. The condition was not linked to the car crash.

Zuma has pleaded not guilty.

He said in a statement read out by his legal representative, Mike Hellens, that he was driving on the M1 south around 10pm. He said it was raining and he lost control after driving through a pool of water.

Shortly after the accident, the National Prosecuting Authority (NPA) decided for the first time not to prosecute based on the existing, insufficient evidence and referred the case to a magistrate’s court or a formal inquest.

Randburg magistrate Lalitha Chetty ruled on December 11 2014 that Zuma was negligent. Chetty found “the death of the deceased Phumzile Dube was prima facie brought about by the negligent act of suspect 2, Mr Zuma.”.

“He failed to conduct himself in a reasonable manner under the circumstances and adverse weather conditions,” she said.

Chetty rejected Zuma’s defence that his car had “aquaplaned” in water as he had admitted to speeding up to overtake a car that was splashing water on the windscreen of his low-slung Porsche.

She said he should have slowed down taking into account the heavy rain falling at the time of the crash.

The NPA, however, initially elected not to prosecute. AfriForum said last April it would seek a private prosecution of Duduzane Zuma for culpable homicide, prompting the NPA to reverse its decision.