Updated

Another person has been arrested in a possible espionage ring based at the U.S. prison camp for terror suspects at the Guantanamo Bay Naval Base.

Ahmed Mehalba, a civilian translator at the camp in Cuba, was arrested Tuesday at Boston's Logan International Airport after it was found that he was carrying classified documents.

He is the third person to be detained for possible security breaches at the naval base, where a largely Muslim, non-English-speaking population of about 660 suspected Al Qaeda (search) and Taliban (search) fighters are being held.

At a brief hearing Tuesday afternoon in U.S. District Court in Boston, Mehalba entered no plea and was detained pending a probable cause hearing scheduled for Oct. 8. On the charge of making false statements, he could face up to five years in prison and a fine of up to $250,000 if convicted.

Mehalba, wearing jeans and an orange golf shirt, said nothing during the hearing, except to tell the judge that he could not afford his own attorney.

Mehalba previously worked as a Boston cab driver. Two days after the Sept. 11, 2001, attacks he applied for a job as a Logan Airport gate guard and was turned down, said Jose Juves, a spokesman for Massport, the agency that operates Logan.

He had no further information on why Mehalba did not get the position. Gate guards perform a variety of jobs, some guarding access to the airfield, some access to the airport, Juves said.

Mehalba is a civilian who formerly served in the Army and twice started but failed to complete a military intelligence course to become an interrogator, two defense officials said on condition of anonymity.

He was medically discharged from the Army in May 2001 and later hired by a private defense contractor to be a translator at the prison in Guantanamo Bay, they said.

Officials said they had no further information on why he didn't complete the courses, nor what the medical discharge was for.

Mehalba was initially pulled aside by homeland security agents from U.S. Customs and Border Protection (search), who did a routine search and found military identification for Guantanamo Bay. Mehalba was asked to present another identification card attached to his belt but he refused, saying it was secret.

He was routed for a second inspection.

Mehalba was carrying a soft-sided garment bag bearing a U.S. Army insignia, a backpack, suitcase, and about 132 CDs, including one labeled "Backup #3 for MO's Profile," according to details from the affidavit filed by Special Agent John F. Van Kleef in support of the complaint against Mehalba.

Mehalba said that the CDs were just music and videos. When asked if he was carrying any Guantanamo Bay documents, Mehalba said "no, not at all." But one document was labeled in reference to detainee information, an official said. Other documents about the prison camps, some labeled "secret," were in Mehalba's possession.

Because Mehalba appeared to have classified information about detainees at Gitmo, other authorities, agents from Immigration and Customs Enforcement (ICE) of the Department of Homeland Security and the Boston Joint Terrorism Task Force responded and arrested Mehalba, DHS said in a statement. The U.S. Attorney's Office for the District of Massachusetts authorized the arrest.

Mehalba, who DHS officials said acted nervously when questioned, denied the documents were his, authorities said. Mehalba, a naturalized U.S. citizen of Egyptian descent, was stopped in Boston on Monday after arriving on a flight from Cairo, Egypt, via Milan, Italy.

Mehalba is being charged with making false statements to government agents. The FBI is getting a warrant to search the computer found in his possession. He is being held in custody. The FBI is now getting warrant to search his computer. More charges are pending.

Boston attorney Michael Andrews was appointed to represent Mehalba by U.S. Magistrate Judge Charles B. Swartwood.

Assistant U.S. Attorney Michael Ricciuti in Boston  would not say whether making false statements was the only charge against Mehalba or whether additional charges would be filed. Documents outlining Mehalba's arrest were sealed by Swartwood on Tuesday morning.

Defense Department officials described Mehalba as a civilian contractor who provided translation services, but it was unclear if he had fulfilled his contract or was still working at the camp.

"This is clearly becoming somewhat of a pattern and it's something that's very troubling," former assistant FBI director Steve Pomerantz told Fox News on Tuesday.

Pomerantz pointed out that since the Sept. 11 terror attacks, boosting the U.S. military and intelligence services' meager supply of Arabic translators has been a huge priority.

"We do put them through a background investigation however, it's certainly possible … with the necessity to hire these people, there may have been some shortcuts taken," Pomerantz said.

Asked whether perhaps the spy ring extends beyond Camp Delta, Pomerantz said: "It's really difficult to say that because a person's from a certain religion or ethnic background ... we should subject that person to some sort of loyalty test beyond what we subject others to … however, you can't hide your head in the sand, you have to find some balance."

Authorities recently charged a Syrian-born Air Force airman who also served as a translator, Ahmad I. al-Halabi (search), with espionage for allegedly sending classified information about the Guantanamo facility to an unspecified "enemy." He also was accused of planning to give other secrets about the prison to someone traveling to Syria.

Al-Halabi apparently had been under investigation before he arrived at the base.

The Air Force Office of Special Investigations began looking into his case in November 2002 while he was a supply clerk at Travis Air Force Base in California. Al-Halabi was sent to the Cuban base weeks later as an Arabic language interpreter for the Al Qaeda and Taliban suspects there.

The most serious of the 32 charges against al-Halabi carries a possible death sentence. The implication is that al-Halabi was helping the prisoners communicate among themselves and with the outside world.

Al-Halabi claims he is innocent. One of his lawyers, Air Force Maj. James Key III, said al-Halabi is a naturalized U.S. citizen and a patriotic American.

Army Capt. Yousef Yee (search), the Muslim military chaplain who ministered to suspected Al Qaeda terrorists at the base, also was arrested this month and is being held while investigators probe whether he should be charged with espionage. Yee was carrying sketches of the prison and documents about detainees and interrogators at the time of his arrest.

Yee and al-Halabi had contact with each other while at the base, officials said. Yee studied in Syria and al-Halabi is Syrian-born.

The recent arrests have shaken up the Pentagon, which has launched a wider investigation to determine the scope of the alleged spy ring.

Army Lt. Col. Pamela Hart, a spokeswoman for the base, said Friday that military authorities strengthened security at Guantanamo Bay in the wake of the arrests.

She said that officials were making certain that restrictions on handling documents, making phone calls and sending e-mails are being followed.

Fox News' Bret Baier, Anna Stolley and The Associated Press contributed to this report.