Andy Coulson, a former editor of Britain's highest circulated Sunday newspaper, News of the World, is reported to be in a UK police station to answer questions over claims of involvement in hacking phones of public figures, reports say.
Coulson could be arrested following Friday's questioning, according to the UK media.
He resigned as the director of communications of David Cameron, the British prime minister, earlier this year over the allegations.
Scottish police were asked on Thursday to investigate evidence given in court by witnesses, including Coulson, following the latest developments in the phone-hacking scandal engulfing News of the World.
Police investigations are now being launched into at least 4,000 hacking victims, Al Jazeera's Lawrence Lee reported from London.
Cameron held a press conference on Friday, where he addressed the scandal and said he took "full responsibility" for hiring Coulson.
Cameron's friendship with another former News of the World editor, Rebekah Brooks, is also likely to prompt questions.
Questions are already being asked about the fate of Brooks.
Although she has admitted to paying police officers for tip-offs, and was in charge of the paper for a long time, it looks like she will keep her job as chief executive of News Corp, the company which owns the paper.
Coulson became the paper's editor in 2003 but resigned in 2007 after Clive Goodman, the newspaper's royals editor, and Glenn Mulcaire, a private investigator, were jailed for hacking phones belonging to members of the royal household.
He was hired by then opposition leader Cameron as a media aide and became the coalition government's communications chief following the Tories' election victory in 2010.
In December, Coulson appeared in court as a witness at the trial of Tommy Sheridan, a Scottish politician. He repeated his statement that he had no knowledge of phone hacking during his time as editor of News of the World.
"In light of emerging developments regarding the News of the World, the Crown has requested Strathclyde Police to enquire into the evidence given by certain witnesses in the trial of Tommy Sheridan," Scotland's Crown Office public prosecutor said in a statement.
Cameron has promised a public inquiry after allegations that News of the World listened to voicemails sent to victims and relatives involved in some of the country's most notorious crimes.
In his remarks on Friday, Cameron called for a new system of press regulation.
"I believe we need a new system entirely," he said.
"It will be for the enquiry to recommend what the system should be like but my starting presumption is that it should be truly independent, independent from the press, so that the public will know that newspapers will never again be solely responsible for policing themselves but vitally independent from government, so that the public will know that politicians are not trying to control or muzzle the press that must be free to hold politicians to account."
The developments came a day after James Murdoch, deputy chief operating officer of News Corp, which owns News of the World's parent company, News International, announced the end of the tabloid.
"News International today announces that this Sunday, 10 July 2011, will be the last issue of the News of the World," Murdoch said.
He said the paper had done good things, but "the good things have been sullied by behaviour that was wrong.
"Indeed, if recent allegations are true, it was inhuman and has no place in our Company. The News of the World is in the business of holding others to account. But it failed when it came to itself".