The criminal investigation into British tabloid practices focused on a second Rupert Murdoch publication Saturday, with the arrest of four current and former journalists from the Sun on suspicion of bribing police.
A police officer was also held, and authorities searched the newspaper's offices as part of an investigation into illegal payments for information.
The arrests spread the scandal over tabloid wrongdoing, which has already shut down Murdoch's News of the World, to Britain's best-selling newspaper.
Murdoch's News Corp. confirmed that the four suspects were current or former Sun employees. The BBC and other British media identified them as former managing editor Graham Dudman, former deputy editor Fergus Shanahan, current head of news Chris Pharo and crime editor Mike Sullivan.
A fifth man, a 29-year-old police officer, was arrested at the London station where he works.
Officers also searched the men's homes and the east London headquarters of the media mogul's British newspapers for evidence.
The investigation into whether reporters illegally paid police for information is running parallel to a police inquiry into phone hacking by the News of the World.
Police said Saturday's arrests were made based on information provided by the Management and Standards Committee of News Corp., the internal body tasked with rooting out wrongdoing.
News Corp. said it was cooperating with police.
"News Corporation made a commitment last summer that unacceptable news gathering practices by individuals in the past would not be repeated," it said in a statement.
In an email to staff after the arrests, Tom Mockridge -- chief executive of Murdoch's British operation, News International -- said the internal investigation into wrongdoing at the Sun "is well advanced."
"News International is confronting past mistakes and is making fundamental changes about how we operate, which are essential for our business," Mockridge said.
"Despite this very difficult news, we are determined that News International will emerge a stronger and more trusted organization," he added.
Thirteen people have now been arrested in the bribery probe, though none has been charged. They include Rebekah Brooks, former chief executive of News International; ex-News of the World editor Andy Coulson, who is also Prime Minister David Cameron's former communications chief; and journalists from the News of the World and the Sun.
Two of the London police force's top officers resigned in the wake of the revelation last July that the News of the World had eavesdropped on the cellphone voicemail messages of celebrities, athletes, politicians and even an abducted teenager in its quest for stories.
Murdoch shut down the 168-year-old tabloid amid a wave of public revulsion, and the scandal has triggered a continuing public inquiry into media ethics and the relationship between the press, police and politicians.
News Corp. is preparing to launch a new Sunday newspaper -- likely called the Sunday Sun -- to replace the News of the World.