The Courtailler brothers grew up in this medieval Alpine town, children of a butcher who went broke, who divorced his wife and moved to a job in a meatpacking plant far away. Two of the three brothers, David and Jérôme, educated in Catholic schools, foundered in drugs until they found religion: Islam.
Within five years of David's initial conversion at a mosque in the British seaside resort of Brighton in 1996, the brothers embraced many of the leading lights of Europe's Islamic terror network. David, 28, is now in jail, and in late June, Jérôme, 29, turned himself in to the police in the Netherlands, days after he was convicted by a court there of belonging to an international terrorist group.
The Courtaillers are part of a growing group of people who found a home in Islam and then veered into extremism, raising concerns among antiterrorism officials on both sides of the Atlantic that the new recruits could provide foreign-born Islamic militants with invisibility and cover, by escaping the scrutiny often reserved for young men of Arab descent.
A handful of Westerners have already been arrested on terrorism charges. Their experiences, the authorities fear, could foreshadow a deepening problem.
"Converts will be used for striking more and more by jihadist circles," said Jean-Luc Marret, a terrorism expert at the Strategic Research Foundation, in Paris. "They have been used in the past for proselytism, logistics or support, and they are operationally useful now."
Islam is Europe's fastest-growing religion, and many experts say that while there are no reliable statistics, they believe that the number of converts has grown since Sept. 11, 2001, in many ways because of the campaign against terrorism.
Antoine Sfeir, a French scholar who is writing a book on the trend, said a small number of converts, many of them disaffected and often troubled young people, saw the current wave of Islamic terrorism as "a kind of combat against the rich, powerful, by the poor men of the planet."
Only a small fraction of Western Islamic converts sympathize with terrorism, and even fewer become engaged in terrorist activity. A few dozen militant converts have been identified so far. A report by France's domestic intelligence agency, published by Le Figaro, estimated last year that there were 30,000 to 50,000 converts in France.
However small the number of them drawn to terrorism, the police are focusing on this subset as a serious and growing threat.
"The conversion to Islam of fragile individuals undoubtedly leads to the risk of diversion to terrorism," the intelligence agency's report said, adding that radical groups have recruited converts because they could cross borders easily or serve as front men for renting accommodations or providing other logistical support.
A Transnational Trend
The trend is not only happening in Europe.
Jack Roche, a British-born Australian taxi driver, converted to Islam, trained in Afghanistan and returned to Australia, where he was recently sentenced to nine years in prison for trying to blow up the Israeli Embassy in Canberra. While planning the attack and videotaping the embassy, he was questioned by a guard, whom he told that he was interested in the district's architecture.
"Is that what it is?" the guard, clearly believing him, casually replied in a conversation recorded on the video and later presented at Mr. Roche's trial. "I didn't think you were going to bomb the joint or anything."
In the United States, Jose Padilla, held by the government on suspicion of plotting terrorist attacks, converted to Islam in 1992 while in a Florida jail.
Both David and Jérôme Courtailler, the French brothers, moved freely through Europe without attracting the kind of attention focused on Arab men, even after the French authorities were notified when David was spotted leaving Afghanistan.
In an interview, one French anti-terrorism official said many recent converts were women, further complicating the standard profile.
Militant converts come to Islam in several ways, most notably through contact with militant Muslims while serving time in Europe's prisons, where the Islamic population has skyrocketed. Richard C. Reid, the so-called shoe bomber from Britain, converted to Islam in prison. France's prison population is more than 50 percent Muslim.
Another door to Islam is the Tablighi Jamaat, a missionary group that started in India 75 years ago to promote Islam in the face of Hindu domination. It is the world's largest network of Islamic proselytizers.
The Tablighi Jamaat send converts to study in countries like Saudi Arabia or Pakistan, where they often meet militant radicals. Several well-known Western converts are Tablighi Jamaat alumni, including John Walker Lindh, the American caught fighting with the Taliban in Afghanistan in 2002, and Hervé Loiseau, a young French man who froze to death while fleeing the American attack on Tora Bora in Afghanistan in late 2001.
Other people convert because of family influence particularly in France, where intermarriage between Christians and Muslims is increasingly common or simple peer pressure in predominantly Muslim neighborhoods.
While there has been a convert presence in Islamic terror since Al Qaeda's first generation emerged from the 1980's war against Soviet troops in Afghanistan, recruitment efforts have been redoubled since the American invasion there, the authorities say. Seasoned Qaeda members have begun recruiting a new generation of militants through European mosques and from among local militant Islamic groups, the police say.
Jérôme Courtailler was among that group, together with the Frenchmen Johann Bonté and Jean-Marc Grandvisir. The three men were arrested in 2001 in connection with a plot to blow up the American Embassy in Paris, a plot begun before the Sept. 11 attacks but scheduled to be carried out after it.
Mr. Bonté converted to Islam while staying with his brother-in-law, Djamel Beghal, an Algerian-born Frenchman and confessed Qaeda member, in Leicester, England, in 1999. Jérôme Courtailler also converted to Islam in Leicester under Mr. Beghal's influence. Mr. Beghal is believed to have been the ringleader of the American Embassy bombing plan, the French authorities say.
The Path to Jihad
The road from convert to jihadist can be remarkably short, terrorism experts say, because someone new to Islam does not have the cultural bearings or religious grounding to resist radical interpretations of Islam, and many come with a romanticized notion of an Islamic conflict with the West.
"The problem is that the less you know about Islam when you come into it, the easier it is for someone to present you with the `forgotten obligation' of jihad," said Steven Simon, a terrorism expert at the Rand Corporation.
David Courtailler went to Brighton in 1996 to break free of his drug habit and found support among conservative Muslims. "For David, Islam ordered his life," said his lawyer, Philibert Lepy.
American investigators said he was soon keeping company with Muslim radicals and stayed for a time at an apartment used by Zacarias Moussaoui, who is now being prosecuted in Alexandria, Va., in connection with the Sept. 11 attacks.
In court testimony, David Courtailler said friends had offered him a trip to Afghanistan to study the Koran. He accepted and was given nearly $2,000 in cash, an Islamabad phone number and a plane ticket to Pakistan. Within days of his arrival he was taken by car over the Khyber Pass to Al Qaeda's notorious Khalden training camp near the Afghan city of Khost.
Mr. Courtailler has testified that he asked for training in bomb making, but that his request was denied because his Arabic was not good enough. His sojourn in Camp Khalden coincided with that of many other Qaeda militants, including Mr. Reid and Mr. Moussaoui, as well as Ahmed Ressam, who was convicted of taking part in a plot in 1999 to bomb Los Angeles International Airport.
When Mr. Courtailler returned to Europe in August 1998, an American intelligence service notified the French that he and three other Qaeda-trained men were on their way. Despite that information, Mr. Courtailler was able to pass through borders undetected, European police officials say, almost certainly in part because of his ethnicity.
According to French antiterrorism officials, a man in London named Omar Deghayes, now at the American military's detention center in Guantánamo Bay, Cuba, gave Mr. Courtailler phone numbers for militants in Spain and Morocco, including one arrested in connection with the Madrid train bombings in March and another now serving a 19-year sentence for his role in suicide bombings last year in Casablanca.
Mr. Courtailler stayed with that second man in Tangier, Morocco. It was not until he returned to France several months later and was arrested for stealing a pair of shoes in Caen in Normandy that French antiterrorism authorities became aware again of his whereabouts. He was charged with having terrorist associations and released on the French equivalent of bail seven months later.
He soon disappeared, traveling again to Britain, where he spent time in Leicester, where Mr. Beghal lived, investigators said. While he was there, his brother, Jérôme, joined him and converted to Islam.
A Web of Conspirators
Investigators now believe that while in Britain in 2000, David Courtailler provided help to a terrorist cell planning a huge bomb attack. His name was on a fake French driver's license found later along with a large quantity of explosives in a Birmingham apartment.
Jérôme Courtailler moved to Rotterdam, where Dutch intelligence agents intercepted his phone calls with various terrorism suspects, including a Tunisian soccer player named Nizar Trabelsi, who was to be the suicide bomber in the American Embassy plot, according to court documents. Jérôme is also believed to have known Mr. Moussaoui and to have met Mr. Reid when he was in the Netherlands buying the shoes that were eventually turned into bombs.
Jérôme Courtailler was arrested days after the Sept. 11 attacks in connection with the Paris plot. Dozens of fake passports were found in his Dutch apartment, together with videos of Chechnya, the attack on the American Embassy in Kenya and Osama bin Laden, and instructions on how to make a bomb.
Investigators say they believe that he was the source of the fake Belgian passports used by the suicide bombers who killed the Northern Alliance leader Ahmed Shah Massoud in Afghanistan on Sept. 9, 2001.
In 2002, a Dutch judge dismissed the charges against Jérôme Courtailler, who was accused of belonging to an international criminal organization, because the evidence consisted mostly of information from illegally obtained wiretaps. For the next two years he lived near St.-Pierre-en-Faucigny under the watchful eye of France's intelligence services.
The Dutch prosecutor in the case appealed the dismissal, and Jérôme Courtailler was convicted and sentenced to six years in prison. He gave himself up in Rotterdam on June 24.
David Courtailler, meanwhile, was also recently convicted of consorting with terrorists with an intent to carry out violent acts. He is now serving what remains of his four-year sentence, having already served more than a year awaiting trial and having had two years of the sentence suspended. Barring new charges, he will be free in about six months.