OTTAWA — CSIS has recruited some Defence Department wizardry to sidestep legal limits on its ability to spy on Canadians travelling abroad. Details of a Federal Court ruling released Tuesday provide a glimpse of the high-tech tools used by spies in the fight against terrorism and espionage. The reasons for a potentially groundbreaking decision by Justice Richard Mosley reveal the Canadian Security Intelligence Service obtained a warrant to monitor two suspects considered threats to Canada late last year. When it got wind the pair were leaving the country, CSIS won court approval to employ the secretive Communications Security Establishment, a wing of National Defence, to ensure the interceptions could continue.An earlier court ruling had made it clear that CSIS could not legally carry out foreign eavesdropping without approval from the country in which the spying takes place.

However, with the help of CSE's extraordinary technical means, the interceptions would be "controlled from within Canada," Mosley said, making the operation legal.

"Information which may be crucial to prevent or disrupt the threats may be unavailable to the security agencies of this country if they lack the means to follow those lines of communication."

The Ottawa-based CSE collects and processes telephone, fax and computer communications of foreign states, corporations and individuals. The federal government uses intelligence gleaned from the interceptions to support troops abroad, catch terrorists and further Canada's economic goals.

The interceptions planned this year by CSIS, though involving Canadians travelling outside the country, were to "take place at the locations within Canada where the calls will be acquired, listened to and recorded," said Mosley's reasons, made public Tuesday.

In January, CSIS filed an application on "urgent grounds" in light of the two subjects' travel plans.

Mosley approved a three-month warrant after a Saturday court session, where he heard from CSIS and a CSE expert who described the electronic spy agency's interception capabilities. In April, he extended the warrant for an additional nine months.

CSE is generally prohibited from spying on Canadians, but it can assist CSIS and police agencies acting under judicial warrants.

CSIS spokeswoman Manon Berube said the decision recognizes that security threats move easily from one country to another, and that countering those threats required a new approach.

"This ruling is important because it recognizes that security threats are global and highly mobile. CSIS can now use this tool to defend Canada's security."

Berube declined to elaborate on the nature of the operation for which CSIS obtained warrants. But she said the techniques approved by the court could apply to all kinds of security investigations.

"I can't go into any operational detail, but I wouldn't limit that to counter-terrorism. I would say it applies to all threats," including spies or terrorists.

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