A: This depends on what you are referring to as fraud. The Arizona Attorney Generals Office handles certain types of misrepresentation. There website is provided here: https://www.azag.gov/complaints
There is civil non-criminal fraud in which case the party that is wronged would need to contact an attorney.
There are other types that may involve contact to your local police, county attorney, or other government agency. It all depends on what you are referring to when you say they are trying to commit fraud.
A: The answer to this depends on several factors. First is whether the certificates are currently even valid. If they are then it will depend on the terms of your grandmother's will, or who would've received the shares in intestacy. There may even be other instruments like a Trust that direct what is to be done with the certificates.
A: You can actually view them at the public access computers at the clerk's office if that's convenient. You can also go online to the Public Access to Court Electronic Records site: http://pacer.uscourts.gov and lookup the information, or you can call 1-866-222-8029. Information about the McVIS phone number I provided is available here http://www.azb.uscourts.gov/default.aspx?PID=87.