Australian opener Cameron Bancroft was seen in troubled waters on Saturday as he was caught on camera hiding a yellow object, that might have been used by the cricketer for ball tampering, during the play on Day 3 of the third Test in Cape Town.
South African pacer Dale Steyn alleged him of ball tampering, sharing the picture of the on-field incident, saying: "Can we talk about this?"
Bancroft was seen rubbing the ball with his hands shortly before tea and then put them back in his pockets.
Later, he was seen taking a yellow 'mystery object' out of his pocket, only to hide it inside his pants. Suspecting a ball-tampering attempt, on-field umpires Nigel Llong and Richard Illingworth inquired what he had in his pocket.
In response, Bancroft pulled out the cover of his sunglasses.
Although the umpires appeared satisfied with Bancroft's explanation on the field at the time and allowed play to continue, match officials could review other footage.
Reverse swing has been a major part of this series, and players can increase that by roughing up the ball with foreign objects, which is strictly prohibited in cricket.
Australia, which were falling a long way behind in the game, appeared desperate for wickets to turn it around.
The Bancroft incident was the latest in a string of contentious moments throughout the series.
On Day 2 on Friday at Newlands, the Australians lodged an official complaint with their South African hosts over what they called the abusive behavior of home fans in Cape Town. Australia coach Darren Lehmann said several of his players had been verbally abused by the crowd, abuse which included references to the players' families. Lehmann called the fans' behavior "disgraceful" and Cricket South Africa ordered an increased security presence in the crowd on Saturday. That included police officers.
(With AP inputs)