LONDON - A 40-year-old American man living in Scotland said Monday he's sorry for posing as a Syrian lesbian blogger who offered vivid accounts of life amid revolt and repression in Damascus, a still-unraveling hoax that has exposed the difficulty of sifting truth from fiction online.

Tom MacMaster said he created the fictional persona of Amina Arraf and the "Gay Girl in Damascus" blog to draw attention to conditions in a Middle East convulsed by change.

"I never meant to hurt anyone," the Edinburgh University grad student wrote in a long apology on the blog. The university said it had suspended MacMaster's computer privileges while it investigated whether he had breached its rules.

And as the deceit unspooled, a second blogger known as Paula Brooks, who posted some of the fraudulent Arraf's comments on a lesbian news site, admitted to being a man who had adopted a fake lesbian persona.

The Washington Post reported late Monday that "Brooks" was a 58-year-old retired US Air Force member named Bill Graber.

Graber admitted the deceit when phoned by the AP. He said he had set up the Lezgetreal.com site to advance the gay and lesbian cause and felt he would not be taken seriously as a straight man.

"LezGetReal was not meant to be deceitful or con anyone," he said.

He also claimed to have helped unmask MacMaster by tracking his posts to computer servers in Edinburgh.

"He would have got away with it if I hadn't been such a stand-up guy," Graber said.

Gay rights activists and bloggers say MacMaster's deceit has endangered real people who are trying to tell their stories in authoritarian societies.

"He completely stole the limelight of real LGBT bloggers and activists in the Middle East and diverted it in a negative way," said Dan Littauer of the website Gay Middle East.

Daniel Nassar, the pseudonym of a Syrian man affiliated with Gay Middle East, said MacMaster had put all gay Syrians in danger.

"If I was living in a country where I could sue this person because he has damaged me and damaged my cause ... then I would," he said.

The blogs about life as a Syrian-American lesbian grabbed international attention soon after they began in February. Alongside video clips and erotic poems, the writer wrote about a childhood in Virginia, daily life as a gay woman in Damascus, the growing protest movement and hopes for a future Syria freed from "dictators and rule by strong men."

A reporter for The Associated Press, who maintained a monthlong email correspondence with someone claiming to be Arraf, found the persona persuasive. The writer spoke about friends in Damascus, and outlined worries about her father and hopes for the future of her country, and seemed very much like a woman in the midst of the violent change gripping Syria.

In the emails, the person acknowledged fudging some details to protect herself and her family, and painted a harrowing picture of fleeing her home.

On June 6, a post on the Arraf site, ostensibly by a cousin, said she'd been abducted by armed men in a Damascus street. The Internet erupted with alarm. A "Free Amina Arraf" Facebook page drew 14,000 supporters. The US State Department said it was making inquiries to establish her identity.

But other bloggers began to go public with their growing doubts about Arraf's authenticity.

Some thought an April 26 post describing how two plainclothes security agents came to her home to detain her and were persuaded to leaving by her father sounded extremely implausible. Syria's hardline security services are not known as being easily dissuaded.

Reporters in Virginia, where Arraf claimed to have grown up, could find no trace of her or her family.

Journalists could find no one who had ever met her - not even Sandra Bagaria, a Montreal woman who was having an online relationship with her and had exchanged hundreds of emails with "Amina."

Online sleuths - including Andy Carvin of National Public Radio and blogger Liz Henry - found that an IP address used by Arraf was based at Edinburgh University and uncovered links between the blogger and an address in Stone Mountain, Georgia owned by MacMaster, a married American man currently studying for a master's degree at the University of Edinburgh.

Then a woman in Britain, Jelena Lecic, came forward to say the photos of "Amina" on the blogger's Facebook page were actually of her. She had been unaware of the theft until she saw her own picture illustrating a British newspaper article about the blogger.

Faced with the mounting evidence, MacMaster first denied it, then confessed, posting an "apology to readers" Sunday on Amina's blog.

Bagaria, Amina's Canadian online girlfriend, tweeted that she felt "deeply hurt."

Joe Stork, deputy director of the Middle East and North Africa division at Human Rights Watch, said the whole episode should serve as a warning to media and rights groups trying to cover the region's uprisings.

"It underscores the age-old principle that you have to know your sources," he said. "You have to know who is feeding you this information."