Australian opening batsman Cameron Bancroft could face-tampering charges after being spoken to by umpires about an object in his pocket during Saturday' s play in the third Test against South Africa.
Television footage appeared to show Bancroft take an object out of his pocket while fielding on the third day of the Test at Newlands.
He was then seen tucking the object down the front of his trousers before he spoke to on-field umpires Nigel Llong and Richard Illingworth.
Shane Warne, the Australian spin bowling great, said on Twitter he was "very disappointed" by the pictures and called on Australia captain Steve Smith to clear up the "mess" in the post-play press conference.
Aiden Markram and AB de Villiers batted South Africa into a strong position, leaving South Africa at 238 for five in their second innings when bad light ended play, an overall lead of 294. The series is tied at one match apiece.
Opening batsman Markram made 84 and De Villiers batted with unusual caution to be 51 not out at the close.
In a series that has featured several incidents between South African and Australian players, there was an increased security presence after Australian players complained about "disgraceful" behaviour by spectators.
Guards were placed near the stairs leading to the dressing rooms and an Australian security official positioned himself near David Warner, the player most targeted by the crowd.
Security officials and police were seen talking to people in the crowd and on at least one occasion took some spectators away.
Markram, out for nought in the first innings, could have completed a "pair" but he was dropped off the fourth ball of the second innings when he edged Mitchell Starc low to the left of Usman Khawaja at gully.
He survived another much more difficult chance on 59 when Smith flung himself to his right at second slip and got his fingertips to a flying edge off Josh Hazlewood.
Smith, who held a world record-equalling five catches in the first innings, had already added to his tally by catching first innings century-maker Dean Elgar off Pat Cummins for 14.
Markram, who made a century in the first Test in Durban, batted solidly despite his lapses and hit ten fours and two sixes in a 145-ball innings. He shared partnerships of 76 with Hashim Amla (31) and 47 with AB de Villiers, who was unbeaten on 18.
Markram was out in the last over before tea when he chipped Mitchell Starc to mid-on where Cummins held a low catch.
De Villiers opened his scoring with a slapped six off the back foot over cover off Cummins but it was the only scoring shot in the first 20 balls he faced as he made a cautious start to his innings.
De Villiers looked determined to bat until deep in the innings and had faced 103 balls by the close.
South Africa bowled out Australia for 255 at the start of the day, a first-innings lead of 56, with Australia adding ten runs before losing their last wicket.
Australia`s last batsman, Josh Hazlewood, hit two fours off Kagiso Rabada before he was caught by Amla at first slip off Rabada off the 17th ball of the day.
In contrast to the first two days, the weather was cool and cloudy and bad light ended play about 40 minutes early.