The remarkable scale of the British phone-hacking scandal has been underlined by a new allegation that its victims may include one of the country’s most notorious murderers. Robert Thompson, now 29, was one of the schoolboy killers of 2-year-old James Bulger in 1993, a case that appalled the country. According to the Sunday Times newspaper, police have recently informed Thompson that News of the World acquired his telephone details—even though, to protect him from revenge attacks, he had been given a secret new identity by the authorities after serving his sentence.

Thompson joins a list of suspected and confirmed hacking victims that includes, notably, the future king, Prince William; half a dozen former cabinet ministers (including a former deputy prime minister); the mayor of London; senior police officers; and leading personalities in sports, cinema, television, business, and the news media. Most sensationally, as The Guardian revealed in July, the list also includes Milly Dowler, a schoolgirl who was missing at the time of the hacking and was found to have been murdered. There are also unconfirmed press reports that families of soldiers killed in Afghanistan and Iraq have been told they were victims, along with bereaved families of those who died in the July 2007 bomb attacks in London.

The total number of people whose voicemails were accessed by News of the World will almost certainly never be known with any accuracy, although the police officer in charge of the inquiry, Deputy Assistant Commissioner Sue Akers, has revealed that the hacking paperwork held by her team contains the phone details of 3,870 people. Only 170 of those had been contacted by police as recently as July, and so great is the task of tracing and informing them that a significant part of the police team has been working on nothing else for months, and is expected to continue in that way for many months more.

Was every one of those 3,870 people hacked? That too will probably never be known, but police policy now is to inform everyone who might have been. If a hacking victim chooses to sue, they are likely to need further evidence—for example, News of the World articles about them for which the source may be voicemails.

One sure thing is that the flow of reports about additional victims will continue for as long as Akers’s officers continue to pay visits to the people on their lists and show them the evidence in the paperwork. Whether they sue or not, many of these names reach the public domain. The soccer star Wayne Rooney, for one, chose to announce his news via Twitter last April: “Scotland Yard detectives came to see me earlier and showed me some documents, looks like a newspaper have hacked into my phone.”

So far, the known cases fall in the period 2002–06, years in which there can be little doubt voicemail hacking was an almost routine method for some working at News of the World. The case of actress Sienna Miller shows how the technique could be used against a celebrity with a high profile: not only did the paper hack three phones she used personally, but they hacked those of about a dozen people close to her, including close friends, publicity staff, and her mother.

In the royal household it was not only the princes who were targets, but also several senior advisers and assistants. In crime cases victims, their relatives, and police officers have all been targets. In politics the targets ranged over all levels and all parties in Parliament, including, conspicuously, the cabinet minister responsible for the media at the time, Tessa Jowell. In sports, it was both players and behind-the-scenes figures, such as agents and players’ union officials.

It is obvious that there was nothing casual about this. It was a professional, targeted intelligence-gathering operation, though the national-security and business implications have barely been addressed. Murdoch employees must have known the movements of people who were potential terrorism targets. And what happened when the hackers heard something significant that was not part of News of the World’s agenda? As an example, say that Jowell, as media minister, received a message relating to BSkyB, the Murdochs’ U.K. television arm: was that information circulated in News International?

The case of Robert Thompson adds a new dimension to such concerns. Nearly 20 years after the Bulger killing, he and his accomplice, Jon Venables, are still hated figures to many. Children at the time of their conviction, they were released in 2001 at the age of 18 and ever since have lived secret lives, with false identities, away from their hometown of Liverpool. That a newspaper acquired Thompson’s mobile-phone details must be a matter of considerable concern to police. (And Sunday Times, which incidentally is also a Murdoch paper, said that detectives would be concerned about a series of “exclusive” reports that appeared in News of the World from 2002 to 2004.)

When the police investigation into phone-hacking concludes—and the first criminal charges may come in the next few weeks—these broader issues will be addressed by a formal inquiry headed by a senior judge, Lord Justice Leveson. There will be a lot for him to get his teeth into.