Not sure I understand

According to http://www.cbc.ca/canada/montreal/story/2006/12/04/qc-spy.html a Russian, who is thought to be a spy, is about to be deported. But I guess I don't understand why. If he is an illegal (without benefit of diplomatic cover) spy, why won't he be put into jail for the rest of his natural existance? If a Canadian was in Russia as an "illegal", getting caught would mean disappearing. But when we catch one of theirs, we send him home (probably at our expense and probably with an apology for having troubled him). I just don't understand.