Rebekah Brooks, the former head of media mogul Rupert Murdoch's British newspaper wing, will face questioning by British parliamentarians on Tuesday following her release on bail on suspicion of bribing police and illegally intercepting voicemail messages.
The phone-hacking scandal surrounding Murdoch's media empire has forced several of his top officials to resign, as well as two of Britain's top police officers.
The London Metropolitian Police Assistant Commissioner John Yates handed in his resignation on Monday, a day after the resignation of his boss Sir Paul Stephenson.
Yates had employed Neil Wallis, a former News of the World executive, who was arrested and released on bail last week on suspicion of conspiring to intercept communications, as a public-relations consultant.
Britain's Guardian newspaper announced on Monday that Sean Hoare, the former News of the World reporter who was the first journalist to allege Andy Coulson, the former editor of the newspaper, was aware of phone hacking by his staff, has been found dead.
Hoare, who worked on the Sun and the News of the World with Coulson before being dismissed for drink and drugs problems, is said to have been found dead at his Watford home.
Hertfordshire police would not confirm his identity, but the force said in a statement: "At 10.40am today [Monday 18 July] police were called to Langley Road, Watford, following the concerns for the welfare of a man who lives at an address on the street.
"Upon police and ambulance arrival at a property, the body of a man was found.
"The man was pronounced dead at the scene shortly after. The death is currently being treated as unexplained, but not thought to be suspicious. Police investigations into this incident are ongoing."
David Cameron, the British prime minister who is on a trip to Africa, has called for an emergency session in parliament on Wednesday to discuss the latest events.
Al Jazeera's Andrew Simmons, reporting from London, said: "This isn't going away.
"It's looking almost certain now that there will be an extension of this parliamentary term, an extra day where the prime minister will come back in an emergency session and again set out pushing this point that he's in the lead."
Brooks' arrest on Sunday had thrown into doubt her appearance in front of a parliamentary committee investigating the phone hacking scandal, which is also due to hear from Murdoch and his son James Murdoch.
But a spokesman for Brooks said on Monday that she had decided to appear.
Brooks, who has denied knowing about the alleged hacking cases, resigned over the allegations at News International's News of the World tabloid, the paper she edited at the time some of the worst offences were alleged to have happened.
Her resignation on Friday was seen as a move to deflect pressure from Murdoch's News Corporation media empire which has been rocked by the crisis.
A statement released on her behalf said she "voluntarily attended a London police station to assist with their ongoing investigation".
But a spokesman for Brooks told the Sun - a News International title which Brooks once edited - that her arrest had been "quite a surprise".
"She was going, anticipating helping with their inquiry. She wasn't anticipating she was going to be arrested." he said.
Cameron, who is cutting short a trip to Africa because of the crisis, on Monday called an emergency session of parliament on Wednesday.
Politicians were due to depart on their six-week summer recess on Tuesday.
Stephenson quit on Sunday in the face of allegations that police officers had accepted money from the tabloid and had not done enough to investigate hacking charges that surfaced as far back as 2005.
The trigger for his resignation appeared to be revelations that he had stayed at a luxury spa at which Wallis, a former News of the World deputy editor, was a public relations adviser.
"I had no knowledge of the extent of this disgraceful practice [of phone hacking]," Stephenson said in a televised statement.
Feared compromising Cameron
Stephenson added that he had not told Cameron about Wallis' employment as a consultant for fear of compromising the prime minister because of Cameron's relationship with Andy Coulson, a former News of the World editor.
Coulson, who resigned from the tabloid in 2007 following the jailing of a reporter for phone hacking, later served as Cameron's press secretary, but resigned after police reopened the inquiry earlier this year. He was arrested on July 8.
"I did not want to compromise the prime minister in any way by revealing or discussing a potential suspect who clearly had a close relationship with Mr Coulson," Stephenson said.
"I believe it would have been extraordinarily clumsy of me to have exposed the prime minister, or by association the home secretary, to any accusation, however unfair, as a consequence of them being in possession of operational information in this regard."
The News of the World, which published its final edition a week ago, is alleged to have hacked thousands of phones, including that of murdered 13-year-old Milly Dowler, sparking a furore that forced Murdoch to close the paper and drop a $12bn plan to buy the highly profitable British satellite broadcaster BSkyB.
Brooks became the focus of widespread anger over the scandal but was initially protected by Murdoch.
Murdoch guided her rise through the male-dominated world of UK tabloid journalism to become editor of the News of the World in 2000 and the Sun's first female editor in 2003.
"Her arrest strikes at the heart of the Murdoch empire and also at the heart of the British political establishment," said Al Jazeera's Barnaby Phillips, reporting from London.
Source: Al Jazeera and agencies