FRANKFURT, Germany -- Arid Uka grew up in a well-kept immigrant neighborhood in Frankfurt as the son of a relatively prosperous, not all that religious family of ethnic Albanians from Kosovo -- a group notable more for their pro-American outlook than for mosque attendance.
But somewhere along the way, Uka turned drastically from his upbringing.
German officials said Thursday the 21-year-old temporary letter sorter with the postal service has admitted targeting Americans when he opened fire with a handgun on a busload of 15 U.S. airmen at Frankfurt's airport on their way to deployment in Afghanistan, killing two and wounding two more.
A federal judge in Karlsruhe on Thursday ordered the suspect held in prison on two counts of murder and three counts of attempted murder pending further investigation.
German investigators said so far the indications are that Uka turned only recently to extremism -- a member of the generation with immigrant background but raised in Europe, who become radicalized to the shock and dismay of their elders.
German officials said that he had contact with other radicals through social networking sites and elsewhere, but it appears he was not part of a terrorist organization.
"From our investigation so far we conclude that he acted alone," Hesse's top security official, interior minister Boris Rhein told reporters. "So far we cannot see a network."
Uka's Facebook page -- with "There is no God but God and Mohammad is his prophet" in Arabic over a map of Kosovo as his profile picture -- was in stark contrast to the unassuming, somewhat standoffish young man the neighbors met in the stairwell.
"He was nice and very quiet -- I would say, shy," said Jessica Friedrich, who went to the nearby elementary school with him and recognized the scowling, eyes-downcast photo of "Abu Reyyan" -- a recently acquired nom de guerre according to Rhein -- as him.
"He was a completely normal guy," said Katharina Freier, who lives across the hallway from the Ukas.
Uka's father, Murat, would not speak to journalists who gathered outside. But he told Kosovo's daily Gazeta Express that family members are shocked.
"Americans are our friends and they have helped us very much. I can never agree with what has happened," he is quoted as telling the newspaper.
Kosovo Albanians are notably pro-American thanks to the U.S.-led NATO air war that halted a Serbian government crackdown on the rebellious province in 1999, when dictator Slobodan Milosevic still ruled in Belgrade.
The air war and subsequent deployment of peacekeepers, followed by UN administration, paved the way for Kosovo's declaration of independence from Serbia in 2008. There is a Bill Clinton Boulevard and statue of the former president in the capital, Pristina.
The family of Murat Uka's brother, Rexhep, lives in the town of Mitrovica in a large, three-story house with spacious garden, leather sofas, halogen lighting and a flat-screen TV -- signs of considerable prosperity in Kosovo, which remains one of the poorest parts of Europe. The only sign of religion in the house was a small wall clock with a picture of a mosque on it.
Rexhep Uka said the suspect's grandfather was a religious leader at a mosque in a village near the Kosovo town of Mitrovica, and that Arid Uka was a devout Muslim himself. But he also said the family was pro-American and was also having a hard time understanding what their nephew was involved with.
"I love the Americans because they helped us a lot in times of trouble," he told the AP.
"We could not imagine something like this would happen because Americans are our brothers," said Behxhet Uka, Arid Uka's cousin. "They are our friends. Arid has been there (Germany) for the past twenty years. He was born there and went to school."
The imam at Frankfurt's Albanian mosque, Ahmed Kajoshi, called the shootings "a great shame and terrible" and stressed the moderation of the Albanian-speaking community, which attracts people from Albania, Macedonia and Montenegro, but only a few Kosovars, who aren't big on mosque attendance. "They come when they have a problem," said Kajoshi, but not regularly. The Ukas did not worship there, he said.
In addition to contacts with radicals on Facebook, an official also confirmed that Rami M., who was picked up in Pakistan last year and extradited to Germany where he faces charges of membership of a terrorist organization, also lived in Uka's building. The official spoke on condition of anonymity because he was not authorized to talk with news media.
It was not clear how much contact Uka had with Rami M., who left Germany in 2009 for Pakistan, but neighbors said they had known one another. His last name has not been made public.
In Washington, a U.S. law enforcement official said Uka was not on any American watch list.
The investigation was still trying to determine whether Uka might have had any help.
Although the U.S. Embassy in Kosovo's capital of Pristina referred to "the act of a single individual," Pentagon spokesman Marine Col. Dave Lapan said was still not clear whether others could have been involved in planning the attack.
"One of the key focuses of the investigation will be to determine whether others were involved in the incident besides the shooter," Lapan said.
Rhein said the suspect's apartment and his computer have been searched. He said investigators believe the suspect had contact with other radical Muslims on a social network site "but there is no network in the sense of a terror cell."
Several of his 128 Facebook friends also said that they knew little about him
One of his Facebook friends said he knew little about him.
"He was very unremarkable and low-key," Kerem Kenan wrote to The Associated Press. "We had no personal contacts. I'm appalled by the incident."
Rising reported from Berlin. Juergen Baetz and Melissa Eddy in Berlin, Tomislav Skaro in Frankfurt, Bassem Mroue in Cairo, Pauline Jelinek and Eileen Sullivan in Washington, Visar Kryeziu in Mitrovica and Fisnik Abrashi in London also contributed to this report.