Editor's note: Since the publication of this story further investigations have been conducted on James Foley's kidnapping, pointing in a different direction. The latest public information is available here.

BOSTON, Mass. — After a five-month investigation inside Syria and the wider Middle East, GlobalPost and the family of missing American journalist James Foley now believe the Syrian government is holding him in a detention center near Damascus.

“With a very high degree of confidence, we now believe that Jim was most likely abducted by a pro-regime militia group and subsequently turned over to Syrian government forces,” GlobalPost CEO and President Philip Balboni said during a speech marking World Press Freedom Day.

“We have obtained multiple independent reports from very credible confidential sources who have both indirect and direct access that confirm our assessment that Jim is now being held by the Syrian government in a prison or detention facility in the Damascus area. We further believe that this facility is under the control of the Syrian Air Force Intelligence service. Based on what we have learned, it is likely Jim is being held with one or more Western journalists, including most likely at least one other American.”

Balboni said that GlobalPost representatives were now meeting with the Syrian ambassador to Lebanon in Beirut to secure his support. The ambassador has delivered letters to the Syrian ministries of defense, interior, information and foreign affairs.

The Syrian government, however, has so far not acknowledged knowing of Foley’s whereabouts.

“We continue to explore all avenues privately and through diplomatic channels to convince the Syrian government to release Jim so that he can return to his family,” Balboni said. “We remain hopeful and totally committed to bringing Jim Foley home safely and as quickly as possible.”

A freelance journalist and veteran of conflict zones, Foley most recently contributed to GlobalPost and Agence France-Presse (AFP). Foley’s family has made regular appeals in the media — and set up a website — seeking information and support for his release.

Foley had set off toward the Turkish border in a car about an hour before his capture. An eyewitness later told GlobalPost that an unmarked car intercepted Foley. The witness said men holding Kalashnikovs shot into the air and forced Foley out of the car.

That was the last anyone heard from him.

“The not knowing is the hardest part. He hasn’t been seen. He hasn’t been heard from. We don’t know the state of his health,” said John Foley, his father, who attended the World Press Freedom Day event in Boston.

“We spend a lot of time in church, a lot of prayer, faith in God,” Foley’s mother, Diane Foley, added.

Foley previously wrote for GlobalPost in Afghanistan, Libya and Syria. In April 2011, while on assignment for GlobalPost, forces loyal to Libyan leader Muammar Gaddafi captured Foley in the eastern part of the country. Two other journalists, American Clare Gillis and Spaniard Manu Brabo, were also captured. A fourth journalist, South African Anton Hammerl, was killed. Foley, Gillis and Brabo spent 44 days in Libyan prisons before being released. Foley later returned to Libya to cover Gaddafi's fall.

Foley had written for GlobalPost periodically since then, including from Syria. His last article for GlobalPost detailed the growing frustration among civilians in Aleppo — Syria's largest city — with the ongoing conflict.

World Press Freedom Day is held every year to evaluate press freedom around the world, to defend the media from attacks on their independence and to pay tribute to journalists who have lost their lives.

In 2012, Syria was one of the most dangerous places in the world for reporters, according to the Committee to Protect Journalists. The organization recorded 28 deaths in 2012, along with numerous kidnappings. This year has been no better.

Austin Tice, another American journalist who worked for the McClatchy Co. and the Washington Post, has also been missing in Syria since Aug. 13.

The violent conflict in Syria has now dragged on for more than two years, killing more than 70,000 people. Evidence that chemical weapons have been used inside Syria has led to increased calls for foreign intervention in recent weeks. But US President Barack Obama said earlier this week that his administration still lacked enough proof to determine who might be responsible for such attacks.