Need help to report a FRAUD family class sponsorship!

[azb]

I know someone who is not legally divorced with his first wife, but they are living separate.  The guy is married to a second woman right now.  (I know some of you reading this post ask how that is possible! well apparently this is allowed in some countries)
The guy and the first wife became Canadian citizens before all these happened.  Now he has applied for the second's wife immigration case and also the child from this marriage.  
First of all, he has not lived in Canada since he has become citizen.  I know he is trying to show that his intention is to stay in Canada.  
But most importantly, as I said before, he has not divorced his first wife.  But, he has got some fake documents which indicate he is divorced.  He has paid the money back in his home country and got a fake divorce certificate.
How can I report it? Can I do it or the only the first wife can report it? Does she need an attorney? What is the procedure?
I also appreciate if someone tells me what kind of documents I need to send? A copy of the guy and his first wife's identity cards are available which includes all the information for their birth, marriage, divorce,  and children.

[Kedeisha]

Well if you have the information maybe calling Canadian Border Services Agency (CBSA) 1-888-502-9060

[wes786]

Here is the 'how to report fraud' page from CIC website. You can either call them or email them to find out exactly what they need from you.


http://www.cic.gc.ca/english/information/protection/fraud/report.asp

[canadianwoman]

You can also send a letter with photocopies of the ID cards and any other proof to the Canadian visa office processing his second wife's PR application. You don't have to sign it.