Updated

LACKLAND AIR FORCE BASE, Texas -- A be-on-the-lookout alert issued last month for 17 Afghan military men who walked away from an Air Force base in Texas has turned out to be just the tip of the iceberg. No fewer than 46 members of the Afghan military have gone absent without leave from the Defense Language Institute’s English Language Center at Lackland Air Force Base in recent years, FoxNews.com has learned.

From a series of interviews with civilians and military personnel conducted over the course of a week, and according to documents obtained from a variety of sources, FoxNews.com has learned that five of these Afghan deserters remain at large; eight are in custody; at least 18 are in Canada and one has been granted conditional U.S. residency.  The most recent to disappear fled the Texas base just last Thursday, hours after his graduation ceremony.

Some of the men disappeared before completing the Defense Language Institute (DLI) program. Others graduated from DLI but vanished before their scheduled flights back to Afghanistan. Many never showed up at the U.S. military base where they were scheduled to attend specialized formal training. A smaller percentage of the group went AWOL while attending the formal training programs.

Military and law enforcement officials say it’s not uncommon for foreign military personnel who come to the U.S. for training to get lured in by hopes of a better life. But the number of AWOL Afghans has become a growing problem.

Last year alone, 21 Afghan military students disappeared from DLI — a much higher rate than students from other countries who attend the school. Two of the men went AWOL weeks after graduating from the program; the others vanished before completing it.

More On This...

"In 2009, the Defense Language Institute English Language Center reported two other students from countries other than Afghanistan went missing," Gary Emery, spokesman for Lackland AFB, told FoxNews.com. "They include one Iraqi who requested asylum in Houston and one Djiboutian whose status is unknown.”

On June 17, FoxNews.com revealed exclusively that a nationwide be-on-the-lookout (BOLO) bulletin had been issued for 17 Afghans who had gone AWOL from DLI.  The alert, which was compiled by the Naval Criminal Investigative Service and the North Texas Joint Terrorism Task Force, included photos and dates of birth of the 17 men and was widely distributed to law enforcement agencies across the country.

FoxNews.com quickly found at least 11 of the 17 AWOL Afghans on Facebook.

Since then, FoxNews.com has learned that the problem of Afghan military members going AWOL is more pervasive than suggested by the June bulletin, which included outdated and incomplete information. The BOLO alert included men who had been apprehended more than six months before it was issued, and it failed to include the name and photo of the most recent Afghan to vanish from DLI — a pilot who disappeared in March — as well as 28 others who have gone AWOL in recent years.

"Since 2002, 745 students have passed through the U.S. on this training and only 46 have actually gone absent without leave, and in 2009 there was a peak of 21 students," Col. Stewart Cowen, NATO spokesman, Afghanistan, told FoxNews.com.

Citing statistics provided by the Department of Homeland Security, Cowen said 25 of the 46 remain unaccounted for.

At least 18 of those are known to be in Canada. (Multiple sources told FoxNews.com that there is believed to be a strong network of former AWOL Afghans now living in Canada or illegally in the U.S., and students can easily find out how to get to Canada or leave town.)

The number of Afghan DLI students and former students who have gone AWOL, by year:

2005: At least one

2006: At least three

2007: Three

2008: At least six

2009: At least 21

2010: At least two

Last year, at least 17 Afghans went AWOL from DLI — and at least four more disappeared after graduation and before or during their next training assignment or before a scheduled flight back to Afghanistan.  Seven students vanished in December alone.

Click here for detailed information about the Afghans who have gone AWOL.

It was only after seeing a dramatic spike in the number of AWOL Afghans late last year that the U.S. and Afghanistan took action to address the problem.

"As the statistics grew, NATO mission in Afghanistan realized there was issue, a new problem that we needed to address," Cowen said.

In January, officials said, the new NATO training mission restructured its system for sending Afghans to the U.S. for training. As part of the new process, biometric information is now taken for each Afghan. There is a stricter vetting process now, and all applicants are required to sign a statement promising not to go AWOL and to repay the costs if they do. The family of Afghan military men who are accepted into a DLI program must now vouch for their return and promise to pay $40,000 if the soldier goes AWOL while in the U.S.

And in January, a full-time liaison, Lt. Col. Wahab Sultany, was appointed to work with Afghan military members in the U.S., charged with ensuring that the Afghan students at DLI and at programs in two other states completed their training and returned home to help build the Afghan military and assist with the U.S. war efforts.

Sultany was very successful; none of the students who arrived during his watch went AWOL from DLI.

But without notice, Sultany was removed from his post last week, and he returned to Afghanistan on Friday. His replacement isn’t expected to arrive for many months. Since Sultany was removed from his position, one Afghan military member has already vanished.

Defense Department spokesman Mark Wright gave FoxNews.com this statement:

"The Department of Defense treats all such incidents very seriously, and we work closely with appropriate federal agencies to respond to each event. These students came here as part of a broader United States engagement with Afghanistan to develop a sustainable Afghan security force. I would also note that while the incidents of Afghan students going AWOL (absent without leave) are a matter of concern, there are thousands of other international students who successfully attend training each year without incident."

FBI spokeswoman Denise Ballew told FoxNews.com, “We have an interest in locating these individuals and we'll refer other questions to ICE.”

DLI, Lackland Air Force Base, U.S. Air Force, NCIS and DHS’ San Antonio office did not respond to FoxNews.com’s requests for comment before publication. The Department of Homeland Security and the U.S. Embassy in Kabul referred requests for comment to Immigration and Customs Enforcement. ICE initially declined to comment early last week and did not respond to numerous follow-up requests regarding additional information.

Additional reporting by Conor Powell