It has to be done in a lab. CDC has done it so I don't know why Canada wouldn't do it on their own. Strange…
I found this interesting, though:
"A large amount of viruses may remain in deceased people infected with SARS-CoV-2, and the survival time of the viruses may be prolonged in refrigerated cadavers."
https://www.tandfonline.com/doi/full/10.1080/20961790.2020.1744400