I have an ITA a few days ago and the online application asks for submission of police certificate from Vietnam (my country of citizenship). I have been in Canada since I was 15. I was back in Vietnam for 3 months (from my 18th birthday onwards) then returned to Canada. I went back to Vietnam again for 3 weeks when I was 20. I am now 23. According to the cic guidelines I don’t need a police certificate. Do I still need to submit one? If not, should I include a letter of explanation?