Two more Canadians have joined the ranks of foreign fighters with the Islamic State of Iraq and Syria (ISIS), CBC News has learned. Both are relatively recent converts to Islam from Calgary — and they are brothers.

Gregory and Collin Gordon converted to Islam and became known to members of Calgary's Muslim community as Abdul Malik and Khalid. Between 2011 and 2012, they shared an apartment in the same downtown Calgary highrise that once housed Damian Clairmont and Salman Ashrafi.

Ashrafi was identified as a suicide bomber in an ISIS operation in Iraq last November that took the lives of 46 people. Clairmont was killed fighting in Syria earlier this year.

Another Calgarian, Farah Shirdon, who once attended a "study group" with Ashrafi, Clairmont and the Gordon brothers, joined ISIS and was reported to have been killed in battle a few weeks ago.

Sources in the Calgary Muslim community have told CBC News that the Gordon brothers disappeared in late 2012, around the same time that Ashrafi and Clairmont are believed to have travelled to Syria.

A prominent member of the downtown prayer hall attached to the Calgary apartment building told CBC News that Greg was quiet and courteous. When told that he had become a jihadi in Syria, the man, who wished to remain anonymous, expressed shock.

He said Greg suffered from sickle-cell anemia and "was constantly in and out of hospital."

Nabil Babiker, a doctor who fled war-torn Sudan for Canada, frequently worships at the downtown Calgary prayer hall. When shown pictures of Collin and Greg, he said he remembered them by their Arabic names.

Collin Gordon, left, and Greg Gordon, right, converted to Islam and became known to members of Calgary's Muslim community as Abdul Malik and Khalid. (Facebook)

"I don’t imagine you’d do very well as a fighter, a jihadi fighter with that disease," said Babiker, who added he's surprised the Gordon brothers would flee Canada for a war zone.

"If they told me that they were going to fight, I would have told them, 'No, don’t go, never go,'" he said. "By virtue of Islam, by virtue of humanity."

Active on social media

As ISIS fighters murdered their way through Syria and Iraq, Collin embraced the terror group, posting on Facebook earlier this year pictures of what appears to be a compound belonging to Rayat Al-Tawheed — or "Banner of God" — a militant group in Syria linked to ISIS that distributes English-language recruiting materials.

Like other Western jihadis, Collin, too, is active on social media and uses the nom-de-guerre Abu Ibrahim Canadi.

He attended the Southern Alberta Institute of Technology (SAIT) and at Thompson Rivers University (TRU) in Kamloops, B.C., where he studied business.

Sources told CBC News the Gordon brothers disappeared in late 2012, around the same time that two other Canadians who died fighting for ISIS earlier this year are believed to have travelled to Syria. (Twitter)

He played volleyball for both SAIT and TRU and friends say he was popular and well-liked on campus. He founded the Kamloops Social Club and threw a number of parties in the city, bringing both Canadian and international musicians to perform in the small south central British Columbian city. And then his life took a turn.

"All I know about Collin is that he moved back home [to Calgary] and started to be hardcore Muslim," said a former friend from university, who did not want to give his name.

The friend said it became increasingly difficult to communicate with Collin due to his religious beliefs — and that’s when he decided to "unfriend" him on Facebook. He had no idea how extreme Collin would eventually become.

No one CBC News spoke with can explain how exactly Collin went from sports, hip hop and tweets about wanting to marry American rapper Nicki Minaj in early 2012, to becoming one among thousands of foreign fighters trying to establish an Islamic state in the Middle East.

Family 'deeply concerned' for brothers' safety

Heartbroken and confused, their parents told CBC News that they raised their children to be peaceful, kind and smart — and that both were well educated and never had any run-ins with the law.

Asking the media for privacy, the parents of the Gordon brothers provided the following statement to CBC News: "We would like all to know we love and miss our sons dearly. We are deeply concerned for their safety. At this time we refuse to speculate with regards to the end of their story. We continue to keep hope alive."

And while their parents are keeping hope alive, Collin’s social media photos portray someone who has become well-adjusted to life as a foreign jihadi.

In a Facebook posting a year ago, Collin Gordon is seen wearing army fatigues and a scarf wrapped around his head. (Facebook)

In a Facebook posting a year ago, he is seen wearing army fatigues and a scarf wrapped around his head. A relative commented on the photo, saying, "When your dad told me that you and Greg joined the Muslim religion he said to me I don't mind what they do as long as they don't turn al Qaeda [sic]. Seeing this picture maybe he was wrong."

Collin responded: "Al-Qaeda are Muslims and I stand by them in this life and the next as I do with any and every Muslim. But I am not affiliated with al-Qaeda physically if that's what you meant."

He didn’t tell his uncle that he had joined a group that was denounced by al-Qaeda for being too violent.

A week after ISIS announced the establishment of a caliphate and Abu Bakr al-Baghdadi named himself the caliph, Collin changed his Facebook profile photo to a still of al-Baghdadi. That same day he tweeted: "The promise of Allah is true," and he urged other Muslims to swear an oath of allegiance to al-Baghdadi.

His other tweets in recent months have commented on the "incredible" infrastructure of the "Islamic State," the need for "jihad" in Gaza, the recent bombing of ISIS-held territory by the United States, and the beheading of American journalist James Foley, which he referred to as "the perfection of terrorism."

In photographs that have emerged on the Twitter accounts of other jihadis in Syria, Collin can be seen cutting garlic as he prepares a meal, playing video games with other fighters and being trained on the use of M16 rifles.

In yet another photo, he is seen in the passenger seat of a car next to a jihadi watching a lecture by Australian-born radical preacher Musa Cerantonio on a smartphone. A report from researchers at King’s College London identified the English-speaking Cerantonio as one of two prominent "new spiritual authorities" who are playing the role of "cheerleaders" by endorsing "violent jihad and support for jihadist organizations operating in Syria."

Unknown number of Canadian ISIS fighters

Last February, Canadian Security Intelligence Service director Michael Coulombe testified before the Senate national security and defence committee hearing that an estimated 130 Canadians had joined terror groups in Syria, Yemen, Somalia and north Africa. Coulombe estimated that 30 of them had left to join groups like ISIS in Syria and Iraq. Many experts estimate that number is now much higher.

In an editorial published recently in the Globe and Mail, Coulombe said that there is "very real prospect" that Canadians who have joined ISIS and other terror organizations overseas could attempt violent acts in Canada.

A psychologist who conducts workshops for Muslim youth in Calgary says if the Gordon brothers are Canadians, "we have to own it."

Mahdi Qasqas has seen enough young men from Calgary leave to become foreign fighters. He is now training operators at one of the city’s distress centres to handle calls about extremism and radicalization. In September, he is organizing a conference aimed at curbing religious extremism in Calgary.

It may be too late for Greg and Collin Gordon, though, as there are still no signs the men wish to return to Canada.

Instead, two months ago Collin tweeted: "Victory or Shahada [martyrdom] in the end win win."