Detectives pursuing British tabloid phone hacking in 2006 quickly concluded that the practice was not confined to a rogue News of the World reporter and identified hundreds of potential victims _ including one of owner Rupert Murdoch's trusted lieutenants, Rebekah Brooks.
Police nonetheless decided not to expand their investigation, a police officer who led the 2006 probe told Britain's media ethics inquiry Wednesday. The decision came partly because police worried that alerting the victims would tip off the perpetrators and compromise the investigation, he said.
"I accept that there were absolutely further leads that we could have followed in this investigation," Detective Chief Superintendent Phil Williams said. "The decision was we were not going to do that."
Williams denied the decision was influenced by the cozy relationship between the force and Murdoch's media empire. But the failure to investigate further meant it took five more years for the scope of the scandal to be made public.
Since last year, it has ensnared Britain's media, political and police establishments.
On Wednesday, the furor claimed one of the jobs of James Murdoch, who stepped down as executive chairman of his father's British newspapers. James Murdoch, whose denials that he had been warned about wrongdoing at the News of the World have been disputed by former colleagues, will focus on the firm's international television business, parent company News Corp. said.
The announcement came as Williams told the inquiry about the origins of the scandal.
Williams said the London force had been contacted in December 2005 by royal family staff who suspected their voice mail messages were being intercepted.
Williams said police soon discovered that illegal eavesdropping was "probably quite widespread" at the News of the World, and beyond, because of a major flaw in cell phone security systems.
Williams said it seemed likely that many in the media, as well as criminals, would have been aware of the vulnerability of cell phones, whose messages could easily be accessed if the users had not changed the factory-set pass codes.
He said police found more than 400 potential victims and the possible first names of other journalists who commissioned phone hacking in the notes of Glenn Mulcaire, a private investigator working for the now-defunct News of the World.
Mulcaire and News of the World royal reporter Clive Goodman were briefly jailed for phone hacking in 2007. No one else has been charged.
The suspected victims included members of the royal family, politicians and even Brooks, then editor of the News of World's sister paper, The Sun, and later chief of Rupert Murdoch's British newspapers.
Most victims were not informed for several years that their phones might have been hacked, but Brooks was told in 2006. Inquiry lawyer Robert Jay said police found that Brooks' phone had been hacked twice a week in 2005, but she declined to join the prosecution of Goodman and Mulcaire.
Brooks has always insisted she was unaware of widespread phone hacking at the News of the World.
The judge-led ethics inquiry, set up last year because of the hacking scandal, is investigating whether corrupt relations between the press and police stymied the initial inquiry, which failed to reveal the scope and systematic nature of the lawbreaking.
Williams acknowledged that in retrospect it had been wrong not to alert more victims at the time, but said he had not wanted news of the inquiry to leak out because it might alert potential suspects.
He said police considered broadening their inquiry, but concluded that would require major new resources that could threaten other operations, including counterterrorism.
By October 2006, Peter Clarke, the Metropolitan Police counterterrorism chief, decided not to expand the hacking probe. It was reopened last year.
Williams denied that close links to Rupert Murdoch's company had played any role in the police decision. "I don't think it was a factor at all," he said.
News Corp. insisted for years that hacking was confined to Goodman and Mulcaire, but now admits it was much wider.
The company has paid damages to about 60 of what police say are hundreds of victims, including actor Jude Law, singer Charlotte Church and the parents of a murdered 13-year-old whose phone was hacked while police were searching for her.
Murdoch shut down the 168-year-old News of the World in July amid public anger at the scale of its wrongdoing.
Leveson Inquiry: http://www.levesoninquiry.org.uk/
Jill Lawless can be reached at : http://twitter.com/JillLawless