Sara Ahmad's voice quavers slightly as she recalls the summer evening nearly 18 months ago when her older brother, Babar, an IT professional, came over for dinner.
The following day Ms. Ahmad answered a knock at the door to find two policemen standing outside on her leafy suburban street. "They said he'd been arrested on a extradition request to the US," recalls Ahmad, a doctor. "I was completely shocked."
Their dinner together was the last time she's seen her brother.
Charged with running websites hosted in the US that promoted and supported Islamic militancy, Mr. Ahmad is still in British custody. He has appealed the extradition order and Britain's High Court will hear the case on Feb. 20. The proceedings will test the ability of Western governments to put on trial Islamic radicals who use the Internet as a key recruiting and organizational tool.
"In the last couple of years the use of the media by militants has grown in sophistication," says Gary Bunt, author of "Islam in the Digital Age" and a lecturer in Islamic Studies at the University of Wales. "It's very difficult to know what can be done," he says.
But while the US government pursues those who operate websites that allegedly encourage terrorism, some argue that the authorities should instead concentrate on shutting down the sites themselves as soon as possible to limit their impact.
"Leaving sites up ... for the convenience of content analysts and translators doesn't save lives," argues A. Aaron Weisburd, who runs a website monitoring jihadists' use of cyberspace. "Such monitoring did nothing to prevent the Internet from being used as the principal means to build support for the jihadists in Iraq, who in turn kill American service men and women."
Observers caution, however, against overstating the significance of such sites.
"Measuring the impact of this material is problematic," says Bunt. "People sympathetic to this material might express it in different ways. It certainly doesn't mean that everyone who reads these sites goes off and does jihad."
Ahmad's case illustrates how seriously the US is taking such websites. His extradition warrant accuses him - among other things - of helping to run azzam.com, one of the earliest and most high-profile English-language pro-jihad websites, which for a time was run by an Internet Service Provider (ISP) headquartered in Connecticut. A federal grand jury in the US indicted Ahmad in October 2004 on four charges, including that of providing material support to terrorists and conspiring to kill persons in a foreign country. If found guilty, he faces life imprisonment.
US Homeland Security official Michael J. Garcia called the indictment "a significant development in our efforts to target those who are alleged to equip and bankroll terrorists via the Internet."
The extradition request describes how websites allegedly run by Ahmad also told Muslims in the West how to send money, volunteers, and equipment - such as night-vision goggles - to the Taliban and Chechen rebels.
"Muslims must use every means at their disposal to undertake military and physical training for Jihad," says one passage posted on azzam.com, now shut down, quoted in the extradition warrant. "Someone who is not able to fight at this moment in time due to a valid excuse ... can start by the collection and donation of funds."
Weisburd argues that such pro-jihad sites represent an immediate and growing threat. His own website, "Internet Haganah" encourages concerned individuals to pressure legitimate Internet companies, often based in the US or Britain, to close jihadist sites that use their servers to distribute material that incites violence.
"Causing websites to be removed, to be set back up again somewhere else, keeps the bad guys busy online," Weisburd says. "The busier they are, the more opportunities we have to locate them and their associates."
But as fast as Weisburd can get the sites taken down, others spring up. And the conflict is evolving in other ways, too.
While the sites Ahmad was accused of running focused on supporting distant conflicts against the Northern Alliance in Afghanistan or the Russians in Chechnya, a new generation of websites aim to encourage Muslims to carry out attacks within the US and Europe.
In December, the Al Safinat Internet forum posted a detailed guide in Arabic to carrying out attacks within America against economic and oil-related targets as part of Al Qaeda deputy Ayman al-Zawahiri's "bleed until bankruptcy" strategy of defeating the US.
One reader suggested that the document, which included detailed maps and plans of the Trans-Alaska pipeline, be made into a single electronic PDF file so that the information could be easily distributed and acted upon to "inflame the final war between them and us, and lead to their downfall."
"The strategy is certainly being taken seriously on the Web and is generating research traffic," reported SITE Institute, a Washington-based independent research body that first spotted the post. Canadian energy firm BC Hydro has reportedly increased its security in response to the posting.
As governments plan measures against those using the Internet to incite jihadist attacks and spread radical ideology, they risk coming under fire for inflaming feelings of fear already endemic among many Muslims in the West.
"If Babar Ahmad is suspected of anything he should be tried in the UK," says Inayat Banglawala, spokesman of the Muslim Council of Britain. "We believe that if his extradition goes ahead it will radicalize many young people and make them feel that they are being treated unjustly in the country in which they were born," he says.