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.