As the scandal enveloping Rupert Murdoch’s media empire expands in Britain, questions are arising on this side of the Atlantic about the scope of News Corp.'s alleged illicit behavior in the US and whether American media might be prone to similar missteps.

Media watchdog groups wanting to know whether the scandal reached the US are pushing for investigations from the US Department of Justice, the FBI, and the Securities and Exchange Commission. Media reports allege that at least one New York City private investigator was offered money to help hack the phone records of 9/11 victims, says attorney Kevin Zeese, who works for Protect Our Elections, a grass-roots activist group.

“Unless we act now, and act quickly,” says Mr. Zeese, “this [is a problem] will only continue to spread.”

The spread of the Murdoch empire is far-reaching, adds Ilyse Hogue of Media Matters. The News of the World had reporters here in the US, and Mr. Murdoch’s US holdings include the Wall Street Journal, the New York Post, as well as Fox Broadcasting.

“Media has become concentrated globally in a few hands, so we see corporate culture often trump the national culture,” says Ms. Hogue.

But the different journalistic cultures in the US and Britain are worth noting, says Stephen Ward, director of the Center for Journalism Ethics at the University of Wisconsin in Madison.

In the US, journalism is considered a profession, with a strong code of ethics, as defined by such groups as the Society of Professional Journalists. But in Britain, he says, training for journalists is largely restricted to trade and technical schools.

“This has fed a culture of doing whatever it takes to get the job done,” he says.

American journalists shouldn't pat themselves on the back too quickly. Lines in US journalism have been getting blurred for a while, says Brant Houston, who holds the Knight Chair of Investigative and Enterprise Reporting at the University of Illinois at Champaign-Urbana.

“We’ve had tabloids in this country for a long time that have paid people for information,” he says. Once that line has been crossed, he says, “I don’t see why you couldn’t have something like what’s going on in Britain happen here.”

The illegal phone hacking, however, has no clear precedent in recent American journalism, says Bruce Rosen, a New York City media attorney with McCusker, Anselmi, Rosen & Carvelli.

“The closest we have come to the kind of phone hacking in the Murdoch scandal here is the 1998 Cincinnati Enquirer/Chiquita scandal, in which the reporter essentially tapped the voice mail of corporate execs,” Mr. Rosen says.

The newspaper, part of the Gannett chain, “was forced to repudiate a story – that appears largely to have been true – in order to get a settlement,” he notes.

The reporter pleaded guilty to federal charges.

“Many media outlets have strict rules about this. But competitive pressures, especially in regard to celebrities – where the coverage is all tabloid all the time, and where hackers have already broken into celebrity cell phones – may have led to this type of action here,” says Rosen.

Nonetheless, he adds, the Murdoch revelations are “a wakeup call for all media.”