This is a fascinating story, and should go a long way towards educating the public on how espionage works.
There are such things as sleepers. There have been sleepers in the U.S. for a very long time. They don’t just come from Russia or the PRC, but also from Iran and other hostile countries.
If mark checks out, I will have to ask him Thursday how he suspects the Russians trained their spies to pass as Canadians.