Damian Clairmont killed fighting with al-Qaeda-linked rebels in Syria

A 22-year-old Canadian-born Muslim convert who left Calgary for Syria in November 2012has been killed by Free Syrian Army (FSA) forces during rebel infighting, CBC News has confirmed.

Mustafaal-Gharib, bornin NovaScotiaas DamianClairmont, was anAcadianwho spent his first years inWedgeport, N.S.

According to sources in Syria and Canada, al-Gharib was injured in battleand subsequently captured and killed by an unknown faction of the FSA in the city of Aleppo.

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Al-Gharibwas reportedly fighting withJabhatal-Nusra, anal-Qaeda-affiliated rebel group consisting of largely foreign extremists.

Jabhatal-Nusrawas designated a terrorist group by the Canadian government in November2013.

The first public indication ofal-Gharib'sdeath came on social media on Tuesday night, when a Twitter account claiming to be run by a rebel fighter who knewal-Gharibpersonallytweeted a martyrdom notice. The notice uses the nameAbuTalhaal-Canadi, another of al-Gharibs monikers.

Troubled teen to extremist

Al-Gharibconverted to Islam following a two-year period of personal anguish in his teensthat included him dropping out of high school, a diagnosis for bipolar disorder and a suicide attempt at age 17.

He had some trouble as a teenager. When he converted to Islam, initially his family thought that this would be the thing that would calm him down. And eventually it did, saidCBC News senior correspondent Adrienne Arsenault, who interviewed al-Gharibs mother last year.

He did seem to find some peace. And then he changed.

Shortly before his20thbirthday, he moved into a boarding house and, according to his mother, became secretive, isolated and very angry, very political, Arsenault said.

In November 2012,al-Gharibinformed his mother that he was leaving Canada for Egypt, where he would study to become an imam.

Several weeks after his departure, however,CSIScontacted his mother and told her thatal-Gharibhad in fact not gone to Egypt, but rather flew to Istanbul and made his way into Syria shortly after,where he joined up with an extremist group.

CSIS told his mother that it had been watching al-Gharib before he left, but it was unable to stop him from leaving.

Al-Gharibs contact with his mother became increasingly infrequent as time passed, and his text messages became increasingly angry about Canada, increasingly determined to be there fighting, saidArsenault, based on conversations with his mother.

Rebels fighting rebels

Infighting among rebel factionsin Syria's north has intensified in recent weeks, with thehardlineextremist organizationIslamic State of Iraq and the Levant (ISIL) reportedly alienating other rebel groups with brutal tactics andenforcement of Sharia law.

WhileISILandJabhatal-Nusraboth recognized branches ofal-Qaedaoriginally fought alongside secular and moderate rebel groups against the forces of PresidentBasharal-Assad,ISILis now focusing its attention on taking control of cities held by other rebel forces.

The push has pitted the ISIL against theFSA, as well as its former alliesJabhatal-Nusra.

U.K.-based Syrian Observatory for Human Rights estimates that nearly 500 people, 85 of them civilians, have died in rebel-on-rebel clashes this month.

Unknown number of Canadians in Syria

Although it remains unclear how many Canadians are fighting in the Syrian civil war, estimates range from a dozen to more than 100, saidArsenault.

BilalAbdulKareem, an American filmmaker who livedamongIslamist fighters for more than a year, told CBC News in September that he had encountered between 20 and 30 Canadians fighting with various rebel groups.

Ali MohamedDirie, a member of the so-called Toronto 18who left Canada on a fake passport in 2012, was killed last year while fighting with Islamist rebels, according to sources close to his family.

Similarly, a Canadian-born convert known asAbuMuslim, who appeared in a Channel 4 documentary in June2013 travelling with a rebel group calledKatibaal-Muhajireen, reportedly took part in araid on an airportin Syrias north.

Reports surfaced from a jihadi group on social media that a Canadian was killed in the attack, but it remains unclear if it was Abu Muslim or another fighter.

CBC News currently has anecdotal evidence of several other Canadian deaths in Syria, but the Department of Foreign Affairs has not provided official numbers.

"We are aware of reports that Canadians have been killed in Syria. We are following the situation closely," saida spokesperson for the Department of Foreign Affairs in an email statement on Wednesday.

"Since April 24, 2011, Canada has advised against all travel to Syria due to the deteriorating situation."

On Wednesday, Foreign Affairs MinisterJohn Baird told reporters that the news of al-Gharib's death didn't "come as a surprise" and that "there is probably more than one Canadian that is fighting with the opposition."

Canada does not have exit controls for people leaving for Syria, and therefore it is very difficult to keep track of potential extremists abroad, saidArsenault.