In the final days, the Turkish Muslim and the two German converts are said to have schemed and ranted like men on the verge of exploding.
During clandestine meetings, including ones at the mountain village hide-out where they allegedly began assembling bombs, Adem Yilmaz, Fritz Gelowicz and Daniel Schneider talked nearly nonstop about potential bombing targets and suicide attack scenarios, German law enforcement officials say. A small army of police listened in through wiretaps, poised to swoop in as the talk got uglier, according to the officials, who asked to remain anonymous because they were not authorized to discuss the case publicly.
"They were basically throwing out ideas, what about this target, what about that one," said one investigator.
"They became almost megalomaniacal," said another.
The trio's arrest this week for allegedly plotting car bomb attacks on Americans in Germany ended an odyssey into fanaticism, officials say. The journey, they say, led from the radical Islamic underworld of gray German towns to fundamentalist Koranic schools in the Middle East to a Turkish-Central Asian nexus in Pakistani training camps aligned with Al Qaeda.
The alleged leader of the militant cell, the wavy-haired Gelowicz, 28, is married to a woman of Turkish descent who wears a burka. He and a dozen other suspects who remain free, mostly Turks or converts radicalized in Turkish circles, allegedly belonged to the Islamic Jihad Union, or IJU, an Uzbek-dominated terrorist group that is said to have directed their activities from Pakistan.
The alleged connection stokes fears of a growth of radicalism in Germany's large Turkish immigrant population.
Germany has approximately 2 million residents of Turkish descent, a community long seen as hard-working and religiously moderate. The Turkish government has tried to keep fundamentalism in check among Turkish immigrants by training imams to serve in diaspora mosques. Far fewer Turks have been involved in terrorism cases in Germany and elsewhere than Arabs from the Middle East of North Africa.
But the alleged plot to commit Europe's bloodiest attacks reflects the kind of extremism that afflicts South Asian communities in Britain and North African groups in France. Experts are concerned about Germany becoming an enticing target for Al Qaeda's efforts to recruit European-based extremists to strike the West.
"We are especially worried about the Turks and the Turkish Germans in this case," an investigator said. "It seems like the propaganda effort is working. Since the invasion of Iraq in 2003, there is more and more Turkish jihad propaganda material on the Internet."
Turkey's proximity to and influence in Central Asia make it a natural geographic gateway for militant networks in the region or for passing through the former Soviet republics to Pakistan or Afghanistan. Turks feel linguistic, religious and ethnic affinities with Uzbeks and others in the region, analysts say.
"A lot of the Turkish Islamists don't fit in with Arab groups," said Zeyno Baran, an expert on Islamic extremism based at the Hudson Institute in Washington. "You can find Turkish fighters more in Albania, Bosnia and Central Asia. The [Uzbek networks] have had strong support in Turkey.
"It's not the same language," she said. "But there are so many similarities, a sense of comfort. There is familiarity with the Uzbeks, who as Muslims are often also less strict in their personal lives, but very strict ideologically."
The radicalization of Gelowicz and others started, officials say, in a fundamentalist mosque in this city of 52,000, a mix of historic neighborhoods and bleak industrial areas on the Danube River about 45 miles southeast of prosperous Stuttgart.
Gelowicz reportedly began attending the Islamic center at age 15 after his parents, an engineer and a doctor, divorced. Founded in the mid-'90s, it was led by a charismatic Egyptian imam, Yehia Yousif, who preached hatred while working as an informant for spy services, investigators say. The worshipers were Turks, Arabs and converts of German origin, they say.
Authorities say Gelowicz threw himself into extremism with reckless ferocity. One of his prime influences, they say, was Tolga Duerbin, a German of Turkish descent who was a trainee at a solar engineering company owned by Gelowicz's father, Manfred. The two young men would become militant leaders bringing together fellow extremists in three cities, officials say.
In a brief interview Friday, Manfred Gelowicz said he had been estranged from his son for some time. He said authorities had played cat and mouse with Fritz for too long after identifying him as an extremist as early as 2004.
"The services could have stopped my son earlier," said the weary-looking Gelowicz. "They knew all about him."
In 2005, police shut down the mosque because of extremist activity, and questioned Fritz Gelowicz about ties to an extremist friend who had trained in Pakistan.
Gelowicz lived in a simple two-bedroom, ground-floor apartment in a hillside lower-middle-class neighborhood of Neu-Ulm. He read the books of Islamist ideologues, including Egyptian Sayyid Qutb, in translations, authorities say.
Like other Europeans who embrace hard-core interpretations of Islam, Gelowicz and Schneider reportedly traveled abroad to study at a Koranic school -- in their case, in Syria. In mid-2006, Gelowicz made his way to a terrorist training facility run by the IJU in northern Pakistan, investigators say.
At different times during the last year and a half, Duerbin, Schneider and half a dozen associates traveled to small facilities in Pakistan where the IJU, Al Qaeda and their allies trained them, investigators say.
It is unclear how and why the Germans allegedly joined the Uzbek-dominated group, which has become more multiethnic as it adopts a global agenda. But a long-standing connection exists between Turkish and Uzbek militants, who used bases in Pakistan to prepare a spate of attacks in Central Asia in 2004, said Baran of the Hudson Institute.
The IJU sent its recruits back to Germany with deadly marching orders, investigators say.
"The handlers of the Germans there are just like investment bankers," an investigator said. "They invest in the training of the young recruits and they want to make sure that they indeed attack U.S. targets when they go back to their home."
U.S. intercepts of communications to Stuttgart helped German police discover that the known radicals had the backing of a dangerous foreign network and mayhem on their minds, investigators said this week.
In a more detailed account Friday, German investigators said the first U.S. intercepts last year had identified Gelowicz as a training camp graduate, but only through a nickname. Subsequent U.S. intercepts early this year focused police on Internet cafes in Stuttgart, where militants were communicating by signing on to the same e-mail account and writing drafts, a technique intended to elude detection by avoiding actually sending messages, the investigators said.
After lengthy stakeouts of three dozen Internet cafes, police determined that Gelowicz was communicating with handlers in Pakistan, investigators say. They were already concerned because, after Gelowicz's brief detention in January on suspicion of scouting a U.S. military base, they say, a search of his apartment had turned up a "martyrdom" video of a fellow militant.
In April, investigators say, U.S. agents intercepted a communication in which handlers urged Gelowicz to accelerate plans.
Police and prosecutors decided that they were facing an urgent threat. The U.S. Embassy in Berlin issued a terrorism warning to its citizens in Germany. Surveillance intensified as police realized that Gelowicz had teamed with Yilmaz, 29, who lived near Frankfurt, and Schneider, 22, who lived in Saarbrucken, to begin acquiring 1,500 pounds of hydrogen peroxide, allegedly for a bomb, a process that had begun in February, officials say.
During the raids this week, police found an IJU manual explaining how to construct the bomb, investigators say.
The investigation at its peak involved 600 police officers. There are 100 men just in the Stuttgart area who have been identified as Islamists in need of monitoring, officials say. German law makes it very difficult to jail someone for suspected terrorist activity unless there is concrete evidence of a violent act in the making.
"The danger will not go away," an investigator said. "Converts and second- or third-generation Turks are still being radicalized, and it takes a lot of work to watch them all."
Special correspondent Laabs reported from Neu-Ulm and Times staff writer Rotella from Madrid.