Hi, meimei01,
Noone here is going to be able to answer your question on an absolute basis. It really depends on the facts and circumstances surrounding your specific case. As someone that was (in a prior life) involved in law enforcement, I certainly understand that, on occasion, completely innocent people are arrested. With this said,
your situation is not something I am personally familiar with and I strongly suggest that you obtain the opinion of a lawyer experienced with Canadian immigration.
I assume (maybe wrongly; the wording of your question leaves some doubt) that you mean that you have already applied or are thinking of applying to become a PR of Canada?
If not and you are already a Canadian PR, then disregard my thoughts in my note below. In that case I hope that someone else can give you some general guidance.
By the way, from what I understand, things could be worse if you failed to disclose a prior arrest (detainment) that happened before you became a PR, even if you were never convicted (see below).
If you are currently in the application process for PR or are considering applying to become a PR, here are my thoughts:
Question #9 on the IMM 0008 form (Schedule 1) has two sub-questions that you will have to consider:
- "been convicted of, or are currently charged with, on trial for, or party to a crime or offence, or subject of any criminal proceedings in any country [YES/NO]"
- "been detained or put in jail [YES/NO]"
If you answer YES to any of these questions you must provide details.
Given that you were arrested (detained), the second question will require you to now disclose the fact that you were arrested and this will undoubtedly perk the interest of "those that decide". If the arrest happened after you submitted your application, but before approval, I believe that you must disclose this as well.
If I were in your position, I'd contact whatever law enforcement agency (agencies?) was/were involved in your case to obtain as much information as possible about why you were arrested and why you were not charged with a crime. Get hard copies of any reports you might be able to obtain and submit them to be matched up with your application.
Also include a complete, honest, description of everything that happened in your own words.
If you were truly innocent then this will maximize your chances. If there's anything out there that you don't disclose and they find it - then you will not be coming to Canada very soon, if at all. I would advise you to proceed with extreme caution and honesty.
I hope this helps.