- NEW: James Murdoch insists he did not know about the scale of wrongdoing
- Rupert Murdoch is to appear Wednesday at the inquiry into British media ethics
- Police and lawmakers are also probing phone hacking and police bribery
- The Murdochs both deny knowing about the scale of illegal actions at their papers
London (CNN) -- James Murdoch, a top executive in his father Rupert Murdoch's media empire, Tuesday stood by his insistence that he knew little about the scale of phone hacking by people working for News Corp.'s British tabloids.
He was testifying before an independent British inquiry into journalistic ethics prompted by phone hacking at his defunct News of the World tabloid.
He told the Leveson Inquiry he did not decide what goes into the company's British tabloids The Sun and the News of the World, relying on his editors to make the decisions.
He already has been called twice to testify before British lawmakers and has consistently denied knowing about the scale of phone hacking at the newspaper.
Rupert Murdoch will appear Wednesday and perhaps Thursday morning, according to the inquiry's website.
Dozens of people have been arrested in criminal investigations into phone and e-mail hacking and police bribery, and police asked prosecutors last week to charge at least eight people.
The suspects include at least one journalist, a police officer and six other people, the Crown Prosecution Service said, declining to name them.
No charges have been filed yet, and the Crown Prosecution Service said it did not know when a decision would be made about charges.
The British government set up the Leveson Inquiry, the independent investigation that summoned the Murdochs, in the wake of the phone-hacking scandal. Two parliamentary committees also are looking into media conduct.
James Murdoch has been hammered particularly hard. He has already been called twice to testify before British lawmakers and resigned from a number of positions with British subsidiaries of his father's media empire.
Murdoch, 39, has consistently denied knowing about the scale of phone hacking at the paper.
He referred to it when he resigned as chairman of British Sky Broadcasting earlier this month, saying: "I am determined that the interests of BSkyB should not be undermined by matters outside the scope of this company."
Rupert Murdoch testified before lawmakers in July alongside his son.
News Corp. shut down its British Sunday tabloid, The News of the World, last summer after public outrage at the scale of illegal eavesdropping its journalists did in search of stories.
The defunct newspaper has been accused of hacking the voice mail of crime victims, politicians, celebrities and veterans.
Police arrested three more people last week, including a journalist at The Sun newspaper, part of Murdoch's News Corp. media empire and Britain's best-selling daily tabloid.
London's Metropolitan Police said the arrests were the result of information provided to the force by News Corp.'s Management Standards Committee, an internal panel set up by the company to probe suspected misconduct.
"It relates to suspected payments to a public official and is not about seeking journalists to reveal confidential sources in relation to information that has been obtained legitimately," the police statement said of the information.
The British lawyer representing dozens of alleged News Corp. phone-hacking victims was in New York last week, exploring options for a U.S. case against the company.
Attorney Mark Lewis told CNN he is representing three or four new clients, one of whom is believed to be a U.S. citizen, who say their phones were hacked while they were on U.S. soil.
There are also many potential new clients, Lewis said.
"As I've been traveling here," he said, "I've been contacted by many people who've had, so they say, similar problems -- not just hacking, but maybe being trailed, or have fallen out with some American Murdoch News Corp. company, and then found themselves, as they would say, at the wrong end of investigations, the wrong end of information gathered."
CNN's Claudia Rebaza and Bharati Naik contributed to this report.
