Police say Sean Hoare, the whistleblower reporter who alleged widespread hacking at the News of the World, has been found dead.
Police said Hoare's death at his home in England was not considered to be suspicious, according to Britain's Press Association news agency.
Hoare was quoted by the New York Times as saying that phone hacking was widely used and even encouraged at the News of the World tabloid under then editor Andy Coulson.
Coulson — who most recently served as Prime Minister David Cameron's communications chief — was arrested as part of the widening investigation into phone hacking and police corruption.
The news of Hoare's death comes just after the spreading scandal forced two of London's top police officers to resign in less than 24 hours and prompted Cameron to call Monday for an emergency session of Parliament.
Scotland Yard chief Paul Stephenson stepped down Sunday night, followed out the door Monday by John Yates, assistant commissioner of London's Metropolitan Police.
Yates was the official who decided two years ago not to reopen police inquiries into phone hacking and police bribery by tabloid journalists, saying he did not believe there was any new evidence to consider.
Detectives reopened the investigation earlier this year and now say they have the names of 3,700 potential victims.
British Home Secretary Theresa May announced Monday that a police inspectorate will examine possible police corruption.
She told legislators that at moments like this "it is natural to ask whom polices the police" and announced that the Inspectorate of Constabulary would look at links between the police and the press in the wake of the phone-hacking scandal.
The high-profile resignations have made it even harder for Cameron to contain the intensifying scandal that is threatening his leadership and knocking billions off of Rupert Murdoch's global media empire.
Parliament was to break for the summer on Tuesday after legislators grilled Murdoch, his son James and Murdoch's former British chief executive Rebekah Brooks in a highly anticipated public airing about the scandal. Cameron said "it may well be right to have Parliament meet on Wednesday so I can make a further statement."
Cameron spoke in Pretoria, South Africa, on the first day of a two-day visit to Africa. He had planned a longer trip, but cut it short as his government faces a growing number of questions about its cozy relationship with the Murdoch empire and a scandal that has taken down top police and media figures with breathless speed.
Opposition leader Ed Miliband said Cameron needed to answer "a whole series of questions" about his relationships with Brooks, James Murdoch and Coulson. Coulson resigned from his post in Cameron's office in January.
"At the moment, he seems unable to provide the leadership the country needs," Miliband said of Cameron.
Cameron insisted his Conservative-led government had "taken very decisive action" by setting up a judge-led inquiry into the wrongdoing at the now-defunct Murdoch tabloid News of the World and into overall relations between British politicians, the media and police.
Still, Cameron is under heavy pressure after the resignations of Stephenson and Yates, and Sunday's arrest of Brooks — a friend of his — on suspicion of hacking and police bribery.
Who is Yates?
Senior police official John Yates was long seen as thoroughly reliable and was given the most sensitive cases to handle.
Once regarded as a "safe pair of hands," the 52-year-old endured prolonged, hostile questions last week from a parliamentary committee over his one-day review in 2009 which concluded that there was no evidence to justify a further investigation.
Previously, Yates led a high-profile case in Britain known as the cash-for-honours inquiry, a 16-month investigation in 2006 and 2007 into whether people who made donations to the Labour Party were offered peerages. No one was charged.
Yates is only the latest casualty of the spiralling scandal. His boss resigned Sunday and 10 people have been arrested.
Sources: Associated Press and CBC News
Brooks released on bail
Brooks was detained and questioned for nine hours Sunday before being released on bail. Her lawyer, Stephen Parkinson, released a defiant statement Monday professing her innocence.
Parkinson said police would "have to give an account of their actions" considering "the enormous reputational damage" Brooks' arrest had caused to the social and political insider.
Brooks' arrest had thrown into doubt her appearance on Tuesday before the committee that also will quiz Rupert and James Murdoch.
But her spokesman, David Wilson, said Monday she planned to attend.
She was the bold chief executive of News International, Murdoch's British newspaper arm, whose News of the World stands accused of hacking into the phones of celebrities, politicians, other journalists and even murder victims. But, the revelation that journalists accessed the phone of Milly Dowler in search of scoops while police were looking for the missing 13-year-old fuelled an explosion of interest in the long-simmering scandal.
At an appearance before U.K. legislators in 2003, Brooks admitted that News International had paid police for information. But she always said she did not know any phone hacking was going on when she was editor of News of the World between 2000 and 2003.
Police under pressure
Police are under pressure to explain why their original hacking investigation several years ago failed to find enough evidence to prosecute anyone other than News of the World royal reporter Clive Goodman and private investigator Glenn Mulcaire.
Stephenson, the police chief, resigned Sunday over his ties to Neil Wallis, a former News of the World executive editor who has been arrested over the scandal. Stephenson said he had nothing to do with the earlier apparently flawed phone hacking inquiry or Wallis, but was resigning to allow his agency to focus on the London 2012 Olympics instead of leadership changes.
But in his resignation speech on Sunday, Stephenson made pointed reference to Cameron's hiring of Coulson.
Cameron retorted that the situations of the government and the police were "completely different," because allegations that police were bribed for information "have had a direct bearing on public confidence into the police inquiry into the News of the World and indeed into the police themselves."
London Mayor Boris Johnson said Monday that Yates had questions to answer about his own links with Wallis, and added that Yates resigned after being told he would be suspended pending an ethics investigation.
Yates will be replaced by Assistant Commissioner Cressida Dick on an interim basis. Dick is highly regarded among her Scotland Yard peers but has drawn criticism in the past for commanding an operation that resulted in the death of Jean Charles de Menezes, a Brazilian man mistaken for a suicide bomber.
Murdoch hopes to protect American assets
Brooks' arrest was the latest blow for Murdoch, the once all-powerful figure courted by British politicians of all stripes.
Now Murdoch is struggling to tame the scandal, which has already destroyed News of the World, cost the jobs of Brooks and Wall Street Journal publisher Les Hinton and sunk the media baron's dream of taking full control of a lucrative satellite broadcaster, British Sky Broadcasting.
Murdoch is eager to stop the crisis from spreading to the United States, where many of his most lucrative assets — including the Fox TV network, 20th Century Fox film studio, the Wall Street Journal and the New York Post — are based.
Sky News reported Monday that News Corp. had appointed a senior lawyer to head an internal probe on phone hacking.
10 arrests so far
Police have already arrested 10 people, including other former News of the World reporters and editors. One, Press Association royal reporter Laura Elston, was cleared by police on Monday. None of the others has yet been charged.
Even more senior figures could face arrest, including James Murdoch, chairman of BSkyB and chief executive of his father's European and Asian operations. James Murdoch did not directly oversee the News of the World, but he approved payments to some of the paper's most prominent hacking victims, including £700,000 ($1.1 million) to Professional Footballers' Association chief Gordon Taylor.
James Murdoch said last week that he "did not have a complete picture" when he approved the payouts.
At Tuesday's committee hearing, which will be televised, politicians will seek more details about the scale of criminality at the News of the World. The Murdochs will try to avoid incriminating themselves or doing more harm to their business without misleading Parliament, which is a crime.
Hinton, too, could face questioning over wrongdoing at the News of the World during his 12 years as executive chairman of News International. But Hinton is an American citizen living in the U.S., so British authorities would have to seek his extradition if he refused to come willingly.
In the latest twist in the legal saga, Britain's Serious Fraud Office, Britain's anti-fraud agency, said Monday it was giving "full consideration" to a request from a lawmaker that it open an investigation into Murdoch's News Corp.
Late Monday, a group of internet hackers claims to have tampered with the website of Rupert Murdoch's Sun newspaper.
Visitors to The Sun's website late Monday were redirected to a page featuring a story saying Murdoch's dead body had been found in his garden.
Lulz Security took responsibility via Twitter, calling it a successful part of "Murdoch Meltdown Monday."
Lulz Security has previously claimed hacks on major entertainment companies, FBI partner organizations and the CIA.