A spectator was ejected from the ground on Friday after India pace bowler S 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 ICC's Anti-Corruption and Security Unit said.
"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."
Sreesanth also endured continued heckling and sarcastic applause from the crowd.