Fanie de Villiers, former South African fast bowler says that he tipped off the camera operators to look for signs of Australian ball-tampering after he suspected that Australians were using underhanded tactics.

The Australia fast bowlers were getting reverse swing pretty early on and De Villers, who is working as a broadcaster in South Africa felt that something was suspicious about the way that reverse swing was working for the tourists.

His suspicions ultimately were proven to be correct as cameras spotted Cameron Bancroft using a sticky tape to tamper with the ball during the third day’s play.

"I said earlier on, that if they could get reverse swing in the 26th, 27th, 28th over then they are doing something different from what everyone else does," de Villiers told RSN Radio on Monday.

"We actually said to our cameramen, 'go out [and] have a look, boys. They’re using something.'

"They searched for an hour and a half until they saw something and then they started following Bancroft and they actually caught him out at the end.

De Villiers suggested that the wicket was not one from the subcontinent where balls start to get ruffled due to barren wickets with very little grass.

"It’s impossible for the ball to get altered like that on cricket wickets where we knew there was grass on, not a Pakistani wicket where there’s cracks every centimetre.

"We’re talking about a grass-covered wicket where you have to do something else to alter the shape, to alter the roughness of the ball on the one side. You have to get the one side wetter, heavier than the other side."

Fanie was certain that Aussies could not have used a legitimate process to get reverse swing so early on.

"Australian teams getting reverse swing before the 30th over, they had to do something. If you use a cricket ball and scratch it against a normal iron or steel gate or anything, anything steel on it, it reverse swings immediately. That’s the kind of extra alteration you need to do."