Here is useful links how to get police certificates from different countries
http://www.cic.gc.ca/english/information/security/index.asp
http://www.canadavisa.com/canadian-immigration-police-clearance.html#K
I think to get PCC in any country you have to present the reasons for this request. But not sure about proof, might be different rules in every country.I would advise you to attach a copy of the covering letter, even if it is not necessary, nothing to lose anyway.
http://www.cic.gc.ca/english/information/security/index.asp
http://www.canadavisa.com/canadian-immigration-police-clearance.html#K
I think to get PCC in any country you have to present the reasons for this request. But not sure about proof, might be different rules in every country.I would advise you to attach a copy of the covering letter, even if it is not necessary, nothing to lose anyway.