LONDON — Ever since he scored a once-in-a-lifetime scoop by uncovering the depths of the phone hacking scandal, people keep telling British journalist Nick Davies that they have even more secrets to tell.

Davies — who became a journalist because of the Watergate scandal that brought down U.S. President Richard Nixon — says the hacking saga that has enveloped Britain's police, politicians and press may ultimately end with the imprisonment of some of the country's power elite.

"There will be some more arrests. Some people will be charged. There will be trials," the 58-year-old journalist told The Associated Press in an interview.

The story unraveled in 2005, when the News of the World tabloid published a story about Prince William's knee injury. Royal household staff told police the only way the newspaper, owned by Rupert Murdoch's News Corp., could have gotten the news was by listening to the prince's voicemail messages.

A police inquiry led to two men working for the tabloid: reporter Clive Goodman and private investigator Glenn Mulcaire. They were jailed in 2007 for eavesdropping on messages left on the cell phones of royal aides, including some from Prince William and his brother Harry. Nothing was done against the tabloid itself.

"It never made sense: This private investigator was hacking into people's voice mail as some unexplained hobby and the News of the World had nothing to with it?" Davies recalls. "About a year passed, and I got a phone call out of the blue from a terrifically good source. He started to fill me in on what the reality really was."

That tip led Davies to find more victims of phone hacking. It also gave him a window into London's police force, which has since been accused of taking bribes for news tips and dropped the hacking investigation in 2007 after the two men were jailed.

"What on Earth was the most powerful police force doing when it captured a mass of criminal activity by this news organization, left it in black plastic bin bags, and said: 'Let's not look too deeply at that?'" he asked.

Even more information started to drip out once celebrity lawyers won court orders to force the police to release data.

But the next big break for Davies came in 2009 when The Guardian newspaper revealed that Murdoch's papers had paid out more than $1.6 million (1 million pounds) to settle lawsuits involving allegations of hacking into phone messages, as well as illegally accessing tax records, social security files and bank statements of politicians, actors and sports stars.

Davies said police had evidence that thousands of people — from celebrities including Gwyneth Paltrow and Sienna Miller to politicians including former Deputy Prime Minister John Prescott — had been targeted by private investigators working for Murdoch's U.K. papers, run by his News International division.

"As that evidence started to emerge, it was disclosed to News International, who suddenly saw the nightmare emerging," he said.

Guardian editor Alan Rusbridger called then-New York Times editor Bill Keller in March 2010 for what Keller described as a project that called for "some dedicated investigative muscle." Three investigative journalists from the Times flew to London and spent five months working on the story.

"We were conscious that we were very isolated," Davies said. "Our credibility was low, because it was easy to say, 'Ah, well, this is just the Guardian being obsessive and weird.'"

In the end, it was the New York Times who got News of The World reporter Sean Hoare to go on the record to say that the tabloid's editor, Andy Coulson, was aware of the practice. Hoare died Monday; the cause of death is pending but has not been ruled suspicious.

"It was slightly scary," Davies recalled. "It's one thing to know you're right, but for all I knew they were going to come back and say The Guardian got this all wrong."

Keller said his team was brought up to speed by Guardian journalists but each fact was verified and reported again by his team.

"The Guardian deserves great credit for resuscitating a story that seemed near death, and for their strong, tenacious reporting," Keller said. "But we made a real difference on this story."

Davies said that since the scandal has widened, he's been getting calls from potential sources at Scotland Yard, News Corp. and celebrities who want to know whether their messages were hacked.

During the interview, he picked up the phone. "It's George Michael," he announced.

But the scandal has even bigger implications for Britain's politicians.

Coulson said he knew nothing about the actions of his royals reporter and private detective but still resigned in 2007. Soon after, then-opposition leader David Cameron hired him as his communications chief and kept him on when he became prime minister in May 2010.

Coulson quit Downing Street when police re-opened the investigation this January.

It wasn't until early July, however, that the scandal exploded. David revealed that the News of the World had allegedly hacked into the phone of a 13-year-old murder victim, Milly Dowler, and may have impeded a police investigation into her 2002 disappearance — as well as giving her family hope that she was alive — by deleting some messages.

Cameron, who has long defended Coulson, has begun to distance himself from his former aide.

"If the state of our knowledge remains as it is, the prime minister is under pressure — he's not in serious danger," Davies said. "If there is some big disclosure of information which we don't know about, then in principle, (Cameron) could be in serious trouble."

Ten people have been arrested, and formal charges could come as early as September.

And Davies continues to report on the scandal. So far, he has written 78 stories.