A man who says he witnessed Gavin Watson's car crash believes he committed suicide.
Speaking to Power FM on Tuesday, a man identifying himself as Mphahlele described the scene that played out before him on Monday.
"It is very sketchy, this thing happened in front of me yesterday morning. I was taking one client to the airport around 05:00 and there was this Corolla in front of me but I thought it was one of the Ubers or the shuttle companies. He was driving at a high speed. I thought maybe that person was running late to catch a flight.
"That Corolla was taking the far right [lane used for rental and underground parking at OR Tambo International Airport]. Then suddenly, in a split second, it goes straight to the pillar, then it turns around. Some bumpers were flying up, and to me it was someone who wanted to commit suicide. I don't believe in some other [conspiracy] theories," he said.
Mphahlele claimed there were no vehicles in front or behind Watson's car.
He told the radio station he had not reported the matter to the police as he was in shock.
Watson died after the Toyota Corolla sedan he was driving collided with a concrete pillar on the road leading to the drop-off and parking sections of OR Tambo International Airport shortly after 05:00 on Monday.
Graphic photographs of the scene, showing Watson lying next to the car have placed the identity of the driver beyond doubt.
Sources, who have first-hand knowledge of discussions in the family, have told News24 they believed he was murdered.
Papa Leshabane, a spokesperson for the family and Bosasa (now known as African Global Operations), would only confirm the family was not ruling out foul play.
News24 has also confirmed with two major airlines that Watson was not booked on any flights out of Johannesburg. The process of checking with other airlines is ongoing.
Earlier on Tuesday, News24 reported that R70 was found in Watson's wallet. His ID and driver's licence were also found by law enforcement officials.
There was no cellphone or luggage in the car. It is possible that the items were removed by thieves, or that Watson left his cellphone at home.