Federal Court Judge Edmond Blanchard determined the evidence constituted "reasonable grounds to believe" Mohamed Mahjoub was a member of two groups engaged in terrorism.
Mahjoub "had contacts in Canada and abroad with Al Jihad and Vanguards of Conquest terrorists," according to a summary of Blanchard's findings released Friday in support of his ruling handed down in October.
Based on secret evidence that was in part supplied by foreign agencies linked to torture, the government had alleged Mahjoub was a senior member of Vanguards of Conquest and was also involved with Al Jihad, both Egyptian terrorist groups.
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In his decision, Blanchard upheld the national security certificate Ottawa imposed on Mahjoub that has severely restricted his freedom for the past 13 years, even though the judge also found the government violated his constitutional rights
But Blanchard ruled the breaches by the government and Canada's spy service had either been remedied or weren't serious enough to warrant throwing out the case.
Mahjoub — who has never been charged with any crime — has denied any terrorist links. He has fought efforts by the government to deport him, citing the risk he would be tortured in Egypt.
The newly released reasoning states Blanchard found the 53-year-old father of three from Toronto used "aliases to conceal his terrorist contacts" and was "complicit" in al-Qaida weapons training in Sudan.
Mahjoub worked on an agricultural project in Sudan run by al-Qaida leader Osama bin Laden in the early 1990s. His lawyers have maintained it was a legitimate business at the time.
But that wasn't the case, according to Blanchard's findings.
"Mr. Mahjoub worked in a top executive position in a Bin Laden enterprise alongside terrorists in Sudan at a time when key terrorist leaders were in Sudan," the judge's reasons state.
"Mr. Mahjoub was trusted by Mr. Bin Laden on the basis of his ties to the Islamic extremist community."
A lawyer for Mahjoub was not immediately available for comment Friday night.
Blanchard also said in his ruling the courts had already addressed one of Mahjoub's key concerns: that the evidence collected by the spy service was tainted by torture.
Over the years of hearings in Mahjoub's case it emerged that the Canadian Security Intelligence Service destroyed the original records it used as a basis for claiming he poses a threat.
The spy service additionally admitted that foreign agencies that provided intelligence to Canada were linked to torture, but made no effort to filter out the information.
Security officials also said they repeatedly listened in to Mahjoub's calls with his lawyers in violation of the sacrosanct concept of solicitor-client privilege.
Blanchard ruled those errors didn't justify tossing out the security certificate case against Mahjoub.
The reasons for Blanchard's ruling were delayed while officials read it to ensure no sensitive national security information became public.
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