http://ca.today.reuters.com/news/newsArticle.aspx?type=topNews&storyID=2006-08-09T111348Z_01_PEK82538_RTRIDST_0_NEWS-SECURITY-CHINA-COL.XML&archived=FalseThe Chinese govt's statement contradicts the report of the conviction/sentence in absentia:
"Huseyincan is a Chinese citizen suspected of having taken part in East Turkestan terrorist activities," a Chinese Foreign Ministry spokesman said.
"The case is being handled according to law and no verdict has been reached yet," he said in a prepared brief statement read to Reuters by telephone.
-- although that could be disingenuous, and be referring to a subsequent charge.
If he renounced his Chinese citizenship in taking Canadian citizenship, China would not necessarily be bound by that. The renunciation might have to be formal, and be made to a Chinese government official or agency. And renunciation might not be accepted, or be effective against prosecution for crimes. This is the case for the US (easiest country to find info about quickly):
http://law.enotes.com/everyday-law-encyclopedia/dual-citizenshipThe U. S. Immigration and Nationality Act (INA) stipulates that anyone wishing to renounce U. S. citizenship must do more than merely claim allegiance to another government. Americans who face prosecution in the United States or who owe back taxes, for example, cannot merely become naturalized citizens of a country that does not have an EXTRADITION agreement with the United States. Under the terms of INA, anyone who wishes to renounce U. S. citizenship must appear in person before a U. S. consular or diplomatic official and sign an oath of renunciation. This must be done in a foreign country (usually it can be done at a local U. S. Embassy or consulate); the renunciation cannot be executed in the United States proper. Failure to follow these conditions will render the renunciation useless for all practical purposes. Moreover, those who renounce their U. S. citizenship are still liable for any tax obligations they have incurred and may still be liable for military service. If they have committed a crime in the United States, they can still be prosecuted.
That's not to say that anything the Chinese government might be doing is
acceptable, just that by treating the individual as a Chinese citizen it may be well within the bounds of the kind of citizenship law applied by many countries, and a third country might be acting just as properly in recognizing China's claim on him. Of course, a country can have a valid claim on an individual, for extradition for the purposes of criminal prosecution even if s/he does not have the citizenship of that country.
(Canada would certainly not honour an extradition request where the underlying offence was a purely political crime.)