This western Canadian city , now a boom town once again because of its accelerating oil business , is reeling with the news that more of its sons have joined to fight with the radical Islamic group called ISIS . A government report issued in late August says 130 Canadian citizens have gone abroad to join terrorist groups , including 30 believed to be fighting in Syria . In Calgary , five of those young men are linked to one downtown apartment building , which has a mosque on its ground floor . That mosque is where a recent convert to Islam , Damian Clairmont , began worshipping in 2012 . Not long after , he slipped away . His mother told CNN that her son said he was going to Cairo to study Arabic . Instead , she says , he flew to Istanbul and later across the Turkish border into Syria . Clairmont 's boyhood friend , Justin Thibeau , says he spoke to Clairmont briefly last December 23 . Thibeau says his friend sounded `` normal , '' just as if he was n't in Syria . Less than a month later , the 22-year-old would be killed on an ISIS battlefield near Aleppo , Syria , fighting against Syrian rebels of the Free Syrian Army . `` I 'd be lying to you if I told you I did n't see this coming , '' Thibeau told CNN . `` If he was there for reasons he thought true , there was nothing that could have stopped him . '' And only a few weeks ago , one of two Calgary brothers who disappeared in 2012 emerged on Twitter , praising the ISIS terrorists who executed freelance American journalist James Foley . Collin Gordon tweeted under his new Twitter name , Abu Ibrahim Canadi . `` The video of James Foley losing his neck is the perfection of Terrorism , '' he wrote . Collin Gordon and his brother Gregory both said that they had joined ISIS after leaving Canada . Another Calgary Muslim , Farah Shirdon , showed up on YouTube , burning his Canadian passport and vowing to bring his fight home . `` This is a message to Canada and all the Americans , '' he says on the video . `` We are coming and we will destroy you . '' Shirdon was also killed . All of this has made Muslim leaders in Calgary say they are deeply concerned about what one of them called `` criminal radicalization . '' A conference discussing this will take place in Calgary on Thursday , the 13th anniversary of the 9/11 attacks in the United States . `` We plan to go beyond primary prevention and focus on how to interrupt criminal acts of violence and even find worst-case scenarios of violent radicals returning from foreign theaters , '' said Madhi Qasas , one of the conference organizers . What is ISIS ? More than 100 Americans fighting in Syria . Opinion : Why Americans leave for jihad .
Officials say more than 100 Canadians are fighting abroad for terror groups , including ISIS . Five of the young male jihadists are linked to a mosque in the western city of Calgary , Alberta . One recent convert left to Syria soon after beginning worshipping there . Friends and Muslim leaders are concerned .