James Murdoch could be called to clarify his testimony on phone hacking after two former employees challenged his claim he hadn't seen evidence suggesting eavesdropping at one of his newspapers went beyond a jailed rogue reporter, a British lawmaker said Friday.

Murdoch's former legal adviser and an ex-editor say they told media mogul Rupert Murdoch's son years ago about an email that suggested the rot at the News of the World was more widespread than previously claimed.

News International said James Murdoch stood by his Tuesday statements to a parliamentary committee, but the allegation could deal a blow to his credibility. The Murdoch family is struggling to limit the damage from the scandal, which has already cost the media empire one of its British tabloids, two top executives and a billion-dollar bid for control of a satellite broadcaster.

Conservative legislator James Whittingdale, who heads the committee, said Friday that Murdoch could be asked to address the contradiction in writing _ but he would not be recalled before the committee.

Meanwhile Scotland Yard, which is still reeling from allegations that it turned a blind eye to the scandal, was asked to investigate another explosive claim: That journalists bribed officers to locate people by tracking their cell phone signals.

The practice is known as "pinging" because of the way cell phone signals bounce off relay towers as they try to find reception. Jenny Jones, a member of the board that oversees the Metropolitan Police Authority, called for the inquiry into the alleged payoffs by journalists at Murdoch's now-defunct News of the World.

James Murdoch, in the grilling by lawmakers on Tuesday, batted away claims he knew the full extent of the illegal espionage at the News of the World when he approved a massive payout in 2008 to soccer players' association chief Gordon Taylor, one of the phone hacking victims.

Murdoch's News International had long maintained that the eavesdropping was limited to a single rogue reporter, Clive Goodman, and the private investigator he was working with to break into voice mails of members of the royal household.

But an email uncovered during legal proceedings seemed to cast doubt on that claim. It contained a transcript of an illegally obtained conversation, drawn up by a junior reporter and marked "for Neville" _ an apparent reference to the News of the World's chief reporter, Neville Thurlbeck.

Because it seemed to implicate others in the hacking, the email had the potential to blow a hole through News International's fiercely held contention that one reporter alone had engaged in hacking. If Murdoch knew about the email _ and was aware of its implication _ it would lend weight to the suggestion that he'd approved the payoff in an effort to bury the scandal.

Murdoch told lawmakers he was not aware of the email at the time, but in a statement late Thursday, former News International legal manager Tom Crone and former News of the World editor Colin Myler contradicted him.

"We would like to point out that James Murdoch's recollection of what he was told when agreeing to settle the Gordon Taylor litigation was mistaken," they said. "In fact, we did inform him of the 'for Neville' email which had been produced to us by Gordon Taylor's lawyers."

Almost at the same time, it announced it had fired yet another journalist in connection with the scandal _ identified in the British media as a former News of the World editor who now works at its sister newspaper, The Sun.

The request for a pinging inquiry, meanwhile, stems from an allegation made by the late Sean Hoare, a former News of the World reporter who spoke to the New York Times about skullduggery at the tabloid.

Hoare _ who was fired in 2005 _ said officers were paid nearly $500 (300 pounds) per trace. The paper cited a second unnamed former News of the World journalist as corroborating Hoare's claim.

Hoare was found dead on Monday at his home near London; police say the death is not suspicious.

Pinging joins a host of alleged media misdeeds being put under the microscope as police, politicians, and the public weigh allegations that journalists at News of the World engaged in years of lawless behavior to get scoops.

Murdoch's News Corp. is trying to keep the damage from spreading to its more lucrative U.S. holdings, including the Fox network, 20th Century Fox and the Wall Street Journal.

What began in 2005 as a slow-burning scandal over one reporter's efforts to spy on voice mails left on the phones of Britain's royal household has exploded into a crisis that has shaken Murdoch's media empire and led to resignations of two of Scotland Yard's most senior officers.

British politicians have felt the heat too, with the country's top two party leaders falling over each other to distance themselves from papers they once both courted assiduously.

Prime Minister David Cameron's former communications director _ Murdoch newspapers veteran Andy Coulson _ came under fresh scrutiny Thursday after it was reported that he did not have a top-level security clearance, which spared him from the most stringent type of vetting.

And there was further intrigue injected into the scandal after Britain's Cabinet Office released correspondence showing that a senior official believed he had had his phone broken into as recently as last year, when Coulson was already in government.

Although the issue had been covered off-and-on over the years, almost exclusively by the Guardian, allegations of illegal behavior at the News of the World have received feverish attention since a July 4 report alleged that someone at the tabloid hacked the phone of 13-year-old murder victim Milly Dowler in 2002 while police were still searching for her.

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Robert Barr and Cassandra Vinograd contributed to this report.