Although the issue had been covered off-and-on over the years

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.

The temperature cooled a bit on Thursday, with Parliament closed for the first day of its summer recess, but the investigation appeared to be intensifying.

London's Metropolitan Police said Wednesday it was assigning 15 more officers to help the 45 already involved in the investigation.

Since the latest phone hacking allegations emerged, London's police chief and the head of its antiterrorist operations have resigned. So have Rebekah Brooks, chief executive of News International, which runs Murdoch's British newspaper division, and Les Hinton, the publisher of the Wall Street Journal who formerly headed News International. Murdoch has shut down the 168-year-old News of the World, leaving 200 employees looking for work, and abandoned his bid to win control of lucrative British Sky Broadcasting.

Shutting News of the World apparently will also cost Murdoch's surviving British newspapers their exclusive access to British athletes ahead of the 2012 London Olympics.

Team 2012, an initiative supporting British Olympians, had signed up News International as its official partner to help raise funds for athletes. But without the News of the World, Team 2012 said News International can no longer meet its contractual obligations, and it is looking for new media partners.