One destination for visa holders is the Truebright Science Academy, a charter school founded in North Philadelphia by followers of Gulen.
An analysis of H1-B visas conducted for The Inquirer showed that the number granted for Gulen charter schools has grown substantially since that 2006 report. More than 2,500 have been issued since 2007.
U.S. Citizenship and Immigration Services granted 509 of the H1-B visas in 2007. In 2010, the total was 839 - a 65 percent increase.
Truebright, which opened in 2007 and has 348 students in seventh through 12th grades, has received 21 visas, including for a school director, counselors, and math and chemistry teachers.
As a public charter school approved by the Philadelphia School District, it receives more than $3 million a year in district money.
The acting chief executive at Truebright, Tansu Cidav, has declined to discuss the school's operation.
Turkish staffers at Truebright are paid more than their American counterparts, state pension records show. In the last school year, a Turkish math teacher who was not certified and spoke little English was paid $54,000; a certified American science teacher was paid $40,200.
Gulen, who is in his early 70s, lives in self-imposed exile in an enclave in Saylorsburg, Pa. A federal judge in Philadelphia granted Gulen a green card in 2008 after Gulen appealed a Department of Homeland Security ruling that he did not meet the criteria to qualify as an "alien of extraordinary ability."
In his appeal, he emphasized his renown as an educational figure. A spokesman for Gulen, Bekir Aksoy, told The Inquirer recently that Gulen had no ties to the charter schools, of which there are more than 120 in 25 states. Aksoy said Gulen may have inspired his followers to found the schools.
As The Inquirer has reported, several federal agencies - including the FBI and the U.S. Departments of Labor and Education - are investigating whether charter employees working in this country on H1-B visas are kicking back part of their salaries to a Muslim movement Gulen founded known as Hizmet, or "Service," according to sources.
The inquiry is being coordinated by prosecutors in Pennsylvania's Middle District in Scranton. Federal officials have declined to comment on the nationwide inquiry, but a former leader of the parents group at a charter school in State College, Pa., founded by Gulen followers confirmed that federal authorities had interviewed her.
Many scholars consider Gulen's movement a peaceable, moderate strain of Islam, and the federal inquiries have nothing to do with terrorism. Nor is there any evidence that the Truebright school has included any religious elements in its curriculum.
In Turkey, however, Gulen's followers have been accused of pushing for an authoritarian Islamic state.
Last month, the government of Recep Tayyip Erdogan - the pro-Islamic prime minister - detained Turkish journalists who had alleged that Gulen followers were infiltrating security agencies.
One of the detained journalists, Ahmet Sik, wrote an unpublished book about Gulen, The Imam's Army. A criminal court in Istanbul recently banned it and confiscated copies of the manuscript. A draft was leaked online a few days ago.
Last week, a Turkish newspaper, Zaman, published a statement from Gulen denying any involvement in blocking the book's publication.
"Many books against me personally have been published," Gulen told the paper, which the U.S. government links to the Gulen movement, according to the documents. "But I have never been engaged in efforts to prevent the publication of a book."
Other U.S. documents released by WikiLeaks detail diplomats' efforts to follow the Gulen movement in Turkey and their growing unease as they observed an increase in its followers heading to the United States to teach.
A report sent from the embassy in Ankara in August 2005 - before Gulen was granted a green card - said Gulenists were worried about negative attitudes toward Gulen in the United States. They traced those attitudes in part to a 2004 FBI report that Gulen's attorneys had obtained through a freedom-of-information request.
The embassy report questioned Gulen's ultimate aims and said the embassy had evidence the movement pressured Turkish businessmen to give money to Gulenist schools and activities.
"We have multiple reliable reports that the Gulenists use their school network (including dozens of schools in the U.S.) to cherry-pick students they think are susceptible to being molded as proselytizers and we have steadily heard reports about how the schools indoctrinate boarding students," the report said.
Many Gulen-sponsored high schools in Turkey are boarding schools. Scholars who have studied the Gulen movement in Turkey have found that many of those students wind up teaching in U.S. charter schools after earning degrees from Turkish universities with Gulen's support.
One of the most detailed reports in the WikiLeaks cache is titled "Fethullah Gulen: Why Are His Followers Traveling?"
Written from Istanbul in 2006, it describes Gulen as "at the apex of a growing global network of organizations that profess a peace-loving, ecumenical vision of Islam."
The writer continued: "Gulen's activities first piqued consular officers' interest several years ago when applicants began to appear seeking to visit a number of charter schools in the U.S. with which consular officers were unfamiliar."
After interviewing "thousands" of Turks seeking permission to travel to the United States, the consular office in Istanbul compiled "a substantial list of organizations that seem in some way affiliated with Gulen." The roster included the Zaman newspaper in Turkey and 30 charter schools the consular office had identified as of May 2006.
The report said that after U.S. authorities in Istanbul and Ankara denied many of the applicants permission to enter the United States on other types of visas, many returned in 2004 seeking H1-B visas "sponsored by Gulen-affiliated science academies."
A disaffected former Turkish teacher who had worked at one of Gulen's charter schools told federal authorities that the movement had divided the United States into five regions. A general manager in each coordinates the activities of the schools and related foundations and cultural centers.
The former teacher also provided a document called a tuzuk, which resembles a contract and prescribes how much money teachers employed on H1-B visas are supposed to return to Hizmet.
Officials at some of the charter schools in the United States, including Young Scholars Charter in State College, have told parents and American teachers that they need to hire Turks for their schools because they cannot find qualified Americans.
But parents and American teachers complain that the Turks employed on H1-B visas - often as math and science teachers - have limited English skills and are paid more than their American counterparts who are certified.
Some have described how uncertified Turkish teachers are moved from one charter school to another when their "emergency" teaching credentials expire. Others recount a pattern of sudden turnovers of Turkish business managers, administrators, and board members.
The H1-B visas, which typically are granted for three years, allow foreign professionals to take jobs in the United States. Employers file applications seeking foreign workers. The program is largely used by companies seeking workers for high-skilled positions in science, math, and technology.
The U.S. government caps the number of H1-B visas approved each year. Citizenship and Immigration Services began accepting applications for fiscal 2012 on Friday.
Contact staff writer Martha Woodall at 215-854-2789 or email@example.com.
Claudio Gatti is the New York correspondent of Il Sole 24 Ore, the leading daily financial newspaper in Italy.