LONDON - Rupert Murdoch's car was mobbed by photographers Tuesday as he arrived for a grilling from U.K. lawmakers about the phone hacking scandal that has swept from his media empire through the London police and even to the prime minister's office.

Murdoch, his son James and the media mogul's former U.K. newspaper chief Rebekah Brooks were all to be questioned at the hotly anticipated hearing. But the elder Murdoch's Range Rover was surrounded as he arrived at the Houses of Parliament three hours early, and it quickly drove off.

Politicians will be seeking more details about the scale of criminality at Murdoch's News of the World tabloid, while the Murdochs will try to avoid incriminating themselves or doing more harm to their business without misleading Parliament, which is a crime.

Lawmakers are also holding a separate hearing to question London police about reports that police took bribes from journalists to provide inside information for tabloid scoops and to ask why the force decided to shut down an earlier phone hacking probe after charging only two people.

Detectives reopened the case earlier this year and are looking at a potential 3,700 victims.

The London police said Tuesday it had asked watchdog to investigate its head of public affairs over the scandal _ the fifth senior police official being investigated. The Independent Police Complaints Commission will look at Dick Fedorcio's role in hiring a former News of the World executive as an adviser to the police.

Fedorcio also was to be questioned by lawmakers Tuesday, along with police chief Paul Stephenson and assistant commissioner John Yates, who both resigned over allegations of too-close ties to Murdoch journalists.

But it was the appearance by the Murdochs and Brooks that was drawing huge public interest.

Members of the public and journalists lined up hours ahead of time in hope of a spot in the small committee room, which holds about 40 people. More will be able to watch in an overspill room, and Britain's TV news channels are anticipating high ratings for the appearance.