When police burst into the newsroom of Britain's largest-circulation newspaper the Sun this week and arrested five journalists, its senior editors fired back with a full-page headline decrying the raid as a "Witch hunt" that "has put us behind ex-Soviet states on press freedom."
It sounded like an ironic twist of fate: Media magnate Rupert Murdoch's top-selling British newspaper, with three million copies sold every day, under fire for tapping phones, paying off police and politicians and hiring spies, was suddenly accusing the police of reading its reporters' love letters and tax files.
It has now become more serious. On Wednesday night, the battle escalated amid reports that the police are now looking not into cases of individual reporters bribing police and senior officials for stories but rather a "serious suspected criminality over a sustained period," involving the newspaper itself placing public officials on the payroll.
"It involves regular cash payments totalling tens of thousands of pounds a year for several years to public officials, some of whom were effectively on retainers to provide information," an official familiar with the investigation told Reuters News Agency.
Mr. Murdoch will be arriving in London Thursday morning to join the fight for the paper's survival. His son, James Murdoch, head of his European operations, faced increasing pressure Wednesday from shareholder groups arguing that his role in the scandals made him unsuitable as a senior executive.
Sun journalists fought back Wednesday by preparing a human-rights case against their own company, Mr. Murdoch's News Corp. They contend that the company's Management and Standards Committee, established in the depths of the scandal last year to root out corruption, had overstepped the principles of press freedom by endangering the reporters' sources and endangering journalism that would be in the public interest.
Geoffrey Robertson, Britain's most famous human-rights lawyer, defended the Sun reporters, writing in the pages of Mr. Murdoch's other paper, the Times, that "the vital public watchdog role of the press may be undermined, and the ability of the press to provide accurate and reliable information may be adversely affected."
This week's implosion of the Sun has echoes of last summer's wave of allegations against the Sun's Sunday sibling, the News of the World, a hugely profitable paper that was forced to abolish itself amid charges that its reporters had tapped the phones of hundreds of celebrities, members of the Royal Family and politicians and placed senior police on its payroll.
It is widely believed that Mr. Murdoch sacrificed the News of the World in order to salvage the reputation of his media empire after the paper's former editor-in-chief, Andy Coulson, became a top aide to Prime Minister David Cameron and then was accused of roles in phone-hacking and payment-taking scandals.
The Sun and its editors have similarly close relationships with current and former prime ministers. Rebekah Brooks, who edited the Sun from 2003 to 2009 and then became chief executive of Mr. Murdoch's British operation News International, was known for her close relationships with Mr. Cameron and with his Labour Party predecessor, Gordon Brown.
Ms. Brooks's personal assistant, Cheryl Carter, who worked with her for years at the Sun, had her passport seized by police this week after she suddenly attempted to move to Australia following her arrest last month in connection with the scandal, according to The Independent.
The police investigation, Operation Weeting, continues, as does a high-level government probe into newspaper invasions of privacy, the Leveson Inquiry.