Yesterday we noted a Canadian report on the jihadis arrested in Toronto, expressing shock that these young Canadian-born Muslims had “somehow become radicalized.”

Well, as details emerge about the suspects, the shocks just keep on comin’. Because amazingly, astoundingly, in some inexplicable way that surpasses all understanding, some of the suspects were probably radicalized in a mosque.

I know. Hard to believe.

MISSISSAUGA, Canada, June 4 — Several of the people arrested by Canadian authorities in a huge counterterrorism sweep over the weekend regularly attended the same storefront mosque in a middle-class neighborhood of modest brick rental townhouses and well-kept lawns.

The eldest of the 17 Canadian residents arrested in the sweep, Qayyum Abdul Jamal, 43, was described by his lawyer as an active member of the mosque, the Al-Rahman Islamic Center for Islamic Education, though not its leader.

“He’s on the board, he’s there regularly, but he’s not an imam,” said Anser Farooq, the lawyer representing Mr. Jamal and three other people from this Toronto suburb who were arrested Friday night and who also attended the same mosque. “He’s one of about a half dozen people who lead prayers at the mosque.”

Representatives of Islamist front groups are doing their best to pretend it’s just one more in a seemingly endless series of unrelated flukes:

“I do not think of him as an imam,” Tareeq Fatah, the communications director of the Muslim Canadian Congress, said. “People like him are freelancers. I don’t fear imams. I fear freelancers who are creating a Islamacist, supremacist cult.”

Right. He’s a “freelancer,” who just happens to be a prayer leader and is on the board of the mosque. Nothing to worry about.

But this must be a tiny minority of fringe extremists, right?

The Al-Rahman Islamic Center for Islamic Education that Mr. Jamal frequented was locked and quiet this morning. A class on the Koran that was scheduled for midday today was canceled. Located in a small strip mall between the Hasty Market and the Café de Kahn, the mosque is one of several Islamic centers that have sprung up in Mississauga in recent years.

Neighbors said the Islamic Center had grown very popular in the last few years. One neighbor said that on Friday nights there are so many pairs of shoes lined up outside the entrance that it is difficult to walk on the sidewalk to get into the stores in the strip mall.