Cricket Australia has defended its probe into the 2018 sandpaper scandal after bombshell allegations made by former opener Usman Khawaja that the entire team knew about the ploy to tamper with the ball.

Eight years after the scandal, Khawaja has claimed Australia used sandpaper in the Test before they were caught for ball tampering in Cape Town and that the entire team was aware of the plot.

It comes ahead of the release of Khawaja’s autobiography, expected to pull back the curtains on the biggest scandal in Australian cricket.

Cricket Australia’s official investigation — which was ring-fenced specifically to the events at Newlands — concluded only Bancroft, captain Steve Smith and vice-captain David Warner were aware of the plot. Smith and Warner were handed year-long bans, while Bancroft served a nine-month suspension.

Khawaja’s other bombshell claims include that Bancroft had first volunteered to use sandpaper on the ball in the second Test of the infamous series in Gqeberha and he was not interviewed as part of the investigation, despite having been a firm advocate for the team taking collective responsibility.

Khawaja said he drew no joy from going public with his version of events, but he had stayed silent long enough.

“It was all of us. Not the batters, not the bowlers, not the staff. All of us,” Khawaja told The Age.

“Even in the change rooms when I was talking to them after the game, I said ‘Take this as a team. We did this as a team. We knew what was going on, and we have to take it as a team’, and so I was always of that stance.

“Obviously, it didn’t work that way, and those three guys got crucified.”

Cricket Australia responded in an official statement later on Saturday, defending the process behind their investigation.

“There has been a great deal of speculation in the eight years since the 2018 Cape Town Test, including extensive media coverage throughout last month’s series in South Africa,” a CA spokesperson said in a statement.

“During this time there has been the ongoing opportunity to present any relevant information, and this remains the case.

“All relevant information presented to CA to date has been properly considered and we remain comfortable with the findings of our integrity process.”

The chapter in Khawaja’s autobiography about the events is dedicated to Bancroft, Smith and Warner. He said feeling the trio had been treated unjustly ultimately compelled him to go public after several years of consideration.

“I’ve seen Davey over the last eight years just get nailed bad over and over again, and it’s taken a big man not to say anything and just to stay quiet. And he’s just copped it and he’s copped it and he’s copped it,” he said.

“And then Bangers (Bancroft) in the same note, particularly, he played a little bit of Test cricket after that, but then never came back in, even though he’s been scoring a lot of runs. He’s been a terrific cricketer for a long time, but I know it’s something that hangs over his head.

“Even Steve Smith. Steve’s lucky, the greatest batsman of my generation. He came back from that, and he’s come back as good as he ever was in that first Ashes series, and it’s kind of been forgotten for him in some respects. But I know he has never ever forgotten that year and how it all panned out.

The West Australian understands Khawaja reached out to Bancroft last week and set him a copy of his book’s chapter about the events in South Africa.

Khawaja said he strongly considered coming forward with his version of events in 2021, after Bancroft said in an interview whether the team’s bowlers were aware the condition of the ball had been illegally changed was “self-explanatory”.

In the wake of Bancroft’s comments, bowling quartet Pat Cummins, Mitchell Starc, Josh Hazlewood and Nathan Lyon released a statement saying it was “disappointing to see that our integrity has been questioned”.

“We pride ourselves on our honesty,” their statement read.

“We did not know a foreign substance was taken onto the field to alter the condition of the ball until we saw the images on the big screen at Newlands.”