The head of Canada's spy service has called Iraq a "post-graduate faculty for terrorism," but it's the threat from what are known as home-grown terrorists that most worries Canadian security services.

Jim Judd, director of the Canadian Security Intelligence Service, told the Toronto Star in an interview last year the spy agency was aware of Canadians who had gone to Iraq to join the insurgency and was concerned about their eventual return to Canada.

Iraq would provide a training ground, and those coming home would be "well-trained, highly effective, dangerous people," Judd said.

However, CSIS believes fewer than 10 Canadians have gone to fight in Iraq.

A far more disturbing trend, security officials say, is what is developing inside Canada's borders citizens who may never have travelled abroad but have been motivated to extremism through radical websites and Internet chat rooms.

Prisons have become a worry for Canadian security services trying to root out home-grown radicalism
An internal 2004 CSIS report entitled Canadian Converts to Radical Islam says such home-grown converts are particularly dangerous because of their familiarity with Western society.

"The perception that the West is attacking Islam on multiple fronts continues to anger the Muslim world and contributes to support for radical views. Converts in particular are prone to extreme views because of their new-found zeal," states the report, obtained under access-to-information legislation.

The case most often cited as an example of this phenomenon involves Mohamed Jabarah, a former St. Catharines, Ont., Catholic school student who is now in a New York jail after reportedly pleading guilty to terrorism charges at a secret hearing. Jabarah reportedly confessed to acting as an intermediary between Al Qaeda and Jemaah Islamiah, a group believed responsible for bombings in Southeast Asia, including the Oct. 12, 2002, Bali blast that killed 202 people.

Saudi Arabian security forces killed Jabarah's older brother, Abdul Rahman Jabarah, in 2003. The 23-year-old was accused of being one of the key organizers of a May 2003 bombing that attacked a Riyadh residential complex that mainly housed foreigners.

Prisons have also become a worry for security services trying to root out radicals.

John MacLaughlan, the director of Canada's Integrated Terrorism Assessment Centre, said in a recent interview that the "captive audience" in prisons provides fertile ground for recruiters because of inmates' sense of "wanting to belong to something that is bigger."

A CSIS report on the issue discusses the phenomenon in the United States and Europe, citing the example of the so-called "shoe bomber" Richard Reid, who converted to "radical Islam" while in a youth detention facility. A section in the report, entitled Radical Islam in Canadian Prisons, was censored before being released to the Star.