In written testimony released by lawmakers on Tuesday, former Murdoch lieutenants poked holes in the dramatic testimony delivered by their ex-bosses before Parliament last month, accusing them of misrepresentations, exaggerations and more.
Claims made by the Murdochs carried "serious inaccuracies," ex-News International lawyer Jonathan Chapman said in a letter to the House of Commons' media committee, rejecting the notion that the two had been kept in the dark by subordinates.
"Nobody kept Mr. James Murdoch or any other News International/News Corporation executives from being in full possession of the facts," he said.
Other former executives contradicted James Murdoch's assertion that he hadn't been aware of a critical piece of evidence implying that illegal eavesdropping had been far more widespread than News International had previously claimed. The evidence, contained in an email apparently addressed to a senior News of the World reporter, appeared to rip apart the company's fiercely-held claim that the illegal espionage campaign was limited to former royal editor Clive Goodman, who'd already been jailed over the practice.
James Murdoch told lawmakers he wasn't aware of the email at the time, but his former legal adviser Tom Crone said that he'd specifically flagged it to his attention during a brief meeting in June of 2008.
"I have no doubt that I informed Mr. Murdoch of its existence, of what it was and where it came from," Crone said in a letter.
Some of the most scathing attacks on Rupert Murdoch came from his former law firm, Harbottle & Lewis, which accused his company of misusing its legal advice.
The London-based firm said it was asked to perform a narrow review of emails at the News of the World following an employment claim made by Goodman, who'd lost his job after pleading guilty to phone hacking in 2007.
In Parliament, both Murdochs presented this as evidence that Harbottle & Lewis had thoroughly vetted the paper - something the law firm rejected.
"There was absolutely no question of the firm being asked to provide News International with a clean bill of health," the law firm said in a statement. It denied Rupert Murdoch's assertion before Parliament that Harbottle & Lewis was commissioned to "find out what the hell was going on" after Goodman's conviction, saying that if it had in fact been asked to do what the elder Murdoch described, it would have refused.
"It appears there has been some confusion in the mind of Mr. Rupert Murdoch, or perhaps he has been misinformed, about the role of the firm," it added.
The attacks on the Murdochs' testimony are latest to pile the pressure on News Corp., which has already had to close the News of the World tabloid and scupper its multibillion pound (dollar) bid for satellite broadcaster BSkyB as the scandal rumbled on through the summer.
The controversy - which centers on allegations that reporters routinely listened to phone messages of public figures and bribed police officers to score scoops - has also claimed the jobs of Prime Minister David Cameron's top media aide, two top Scotland Yard officials and several long-serving newspaper journalists.
The near-daily revelations about past misbehavior have largely stopped, but the focus is shifting to the issue of whether James and Rupert Murdoch told the truth when they denied knowing what was going on at their newspapers.
Former newspaper editor Paul Connew told Sky News television that the publication of the new allegations that the pair misled Parliament "has been one of the startling developments of the saga so far." He predicted that Rupert Murdoch "will have to look very carefully at whether James' position is tenable."
The long-simmering scandal was first aired in 2006, when Goodman was arrested.
The correspondence released Tuesday included a 4-year-old letter by Goodman warning of what many have long suspected - and what News International has long denied - that eavesdropping was widely used at the News of the World and that senior figures there approved the practice.
The letter also alleges that Goodman was repeatedly promised his job back as long as he did not implicate anyone else at the News of the World during his trial - buttressing allegations that the newspaper group had tried to buy his silence.
"If Goodman's letter is accurate ... the whole foundation of the company's defense for the last three years collapses," opposition lawmaker Tom Watson told Sky. "Day by day, week by week, we're slowly getting the facts."
Watson was one of the committee members who said it was likely to recall James Murdoch to answer more questions about phone hacking at the News of the World, telling journalists earlier that "it is likely we will take Murdoch back."
"There seems to be a question as to whether James Murdoch himself misled the committee," Watson said. "We have not reached a conclusion on that."
Committee Chairman John Whittingdale said there are no plans to recall Rupert Murdoch, who gave evidence to the committee alongside his son on July 19.
Meanwhile, police are investigating claims the News of the World illegally accessed cell phone messages and bribed police to get information on celebrities, politicians and crime victims.
News International said in a statement Tuesday that "we recognize the seriousness of materials disclosed to the police and Parliament and are committed to working in a constructive and open way with all the relevant authorities."
It did not address the specifics of the allegations made against the Murdochs.
