Rebekah Brooks, former editor of News of the World, was arrested, then released, as London police investigate a phone hacking scandal.
LONDON (CNNMoney) -- The widening phone-hacking scandal that brought down one of Britain's biggest newspapers claimed another casualty Sunday, as authorities arrested the paper's former editor, Rebekah Brooks.
Authorities arrested former News of the World editor Brooks on Sunday in connection with British police investigations into phone hacking and police bribery, her spokesman David Wilson said. She was released around midnight -- 12 hours after her arrest.
Brooks will testify as scheduled Tuesday before British lawmakers investigating illegal eavesdropping by journalists, despite her arrest and release over the weekend, Wilson said.
She was being quizzed by police in London after having come in by appointment, a Metropolitan Police spokesman said. Brooks did not know she was going to be arrested when she arrived, said her spokesman.
The police agency does not release names of suspects arrested, and police officials referred CNN to a statement describing an unnamed 43-year-old woman's release when asked whether Brooks remained in custody.
Brooks' spokesman told CNN she was at home early Monday morning. Scotland Yard said the woman was released on bail, and is scheduled to return to a London police station in October.
Brooks resigned on Friday as chief executive of Rupert Murdoch's News International, which published the News of the World and is part of News Corp (NWSA, Fortune 500).
The company also did not know she was about to be arrested when it accepted her resignation, a News International source told CNN Sunday -- asking not to be named discussing internal corporate affairs.
Mark Stephens, a prominent British media lawyer, told CNN the arrest was "somewhat theatrical," given that Brooks has apparently not been charged with a crime.
Brooks had asked police since January whether they wanted to speak with her, but was told that was not needed, her spokesman said. While she received a call Friday to come in Sunday and answer questions, she was not told she would be arrested on arrival, Wilson said -- adding that it came as a shock to Brooks.
Brooks is adamant that she is innocent of any wrongdoing, Wilson said.
"As chief executive of the company, I feel a deep sense of responsibility for the people we have hurt, and I want to reiterate how sorry I am for what we now know to have taken place," she said in a statement Friday.
Brooks is the eighth person arrested in connection with the phone-hacking probe and the fourth arrested in the bribery investigation, police said Sunday. Two people -- including Brooks -- have been detained over both probes, meaning a total of 10 people have been arrested.
News International said Sunday before the arrest that it would "not tolerate wrongdoing," and was determined to rebuild its reputation.
Meanwhile, London's police chief, Metropolitan Police Commissioner Sir Paul Stephenson, announced his resignation because of the hacking scandal.
"As commissioner, I carry ultimately responsibility for the position we find ourselves in. With hindsight, I wish we had juggled some matters involved in this affair differently. I didn't and that's it," Metropolitan Police Commissioner Sir Paul Stephenson told reporters.
Stephenson stressed Sunday that he had behaved ethically, but said he decided to resign because increased scrutiny connected to the case would burden his department and detract from its accomplishments.
"I have taken this decision as a consequence of the ongoing speculation and accusations relating to the Met's links with News International at a senior level," said Stephenson, who became commissioner in 2009 of the Metropolitan Police, which also is known as Scotland Yard.
News International said it would compensate those affected by its illegal phone hacking, cooperate fully with the police and had hired a law firm to "examine past failings," and recommend new procedures to make sure they are not repeated.
The promise comes in national newspaper advertisements in all the major Sunday British newspapers -- a group that does not include the News of the World for the first time in 168 years.
Murdoch closed the paper last week -- less than a week after it came out that reporters working for him had illegally eavesdropped on the phone of a missing girl, Milly Dowler, and deleted some of her messages to make room for more. She was later found dead.
Closing the paper has not put an end to the scandal, which has exposed the close links the British press has with both politicians and the police.
Media baron Murdoch apologized to the British public with full-page advertisements in seven national newspapers Saturday.
"We are sorry," says Saturday's ad, which was signed by Murdoch.
Murdoch's apology comes after his media empire lost two top executives Friday. Brooks on Friday resigned from her post as chief executive at News International, the British arm of Murdoch's News Corp. Hours later, her predecessor, Les Hinton resigned.
Police in the United Kingdom have identified almost 4,000 potential targets of phone hacking, in documents recovered from a private investigator working for the paper.
There were also allegations that News Corp. reporters may have bribed police officers.
Murdoch's campaign of contrition started 12 days after the scandal first broke and barely a week after the News of the World, Britain's best-selling Sunday tabloid, was shut down by News International in the face of public outrage.
Murdoch, Brooks and his son James are to appear before British politicians Tuesday to answer questions over the phone hacking scandal.
Meanwhile, the FBI is also investigating News Corp. after a report that employees or associates may have tried to hack into phone conversations and voicemails of September 11 survivors, victims and their families.
Murdoch's News Corp. encompasses Fox News, The Wall Street Journal, the New York Post and Harper Collins publishers in the United States. News International -- a British subsidiary of News Corp. -- owns the Sun, The Times and The Sunday Times in Britain.
CNN's Andreena Narayan, Atika Shubert, Anna Stewart and Bharati Naik contributed to this report. 
