Lawyers say the driver in a 2010 crash that killed former South African President Nelson Mandela's great-granddaughter has been acquitted.

Hulme Scholes said Tuesday that 25-year-old Sizwe Mankazana was found not guilty on all counts. Mankazana faced charges of driving under the influence, reckless driving and culpable homicide.

Mankazana was driving Zenani Mandela, 13, home from the Soweto concert that kicked off the 2010 FIFA World Cup when he hit a steel barrier. Zenani died at the scene.

Scholes says the magistrate described the crash as a "freak accident," according to the South Africa Press Association. He said the state failed to identify that mechanical failure was likely caused the accident.

Zenani's grandmother Zindzi -- Nelson Mandela's daughter -- is fronting a new United Nations campaign for road safety.