A spectator was ejected from the ground on Friday after India's Shanthakumaran Sreesanth complained to the umpires about verbal abuse on the second day of the first Test against South Africa.
"The player complained to the umpires about being verbally abused," Arrie de Beer of the International Cricket Council's Anti-Corruption and Security Unit told reporters.
"Myself, fourth umpire Brian Jerling and security personnel were asked to go over to the spectator concerned and he was removed from the ground by security. It is unclear at the moment whether the abuse was racial or not," he added.
The incident was the low point of a miserable day for Sreesanth, who allowed two balls to go through him for boundaries at fine leg and who conceded 71 runs from 19 wicketless overs.
He also endured continued heckling and sarcastic applause from a section of the crowd behind him.