Contact your local law enforcement agency.
If the owner reported it stolen and could provide the serial number, most likely the gun was entered into the NCIC (National Crime Information Center) database. Any law enforcement officer should be able to query the database to see if the gun is entered. If the owner could not provide the serial number, or it was filed off, chances are it will be much harder to trace.
at an illegal firearms store? No one here is going to tell you how to acquire an illegal firearm. It is illegal to purchase a stolen firearm or for a felon to purchase a firearm.
If you're found to be in possession of a stolen firearm, expect to be taken into custody. If their investigation determines that you were knowingly in possession of a stolen firearm, then you'll be charged.
Report it.
Yes
When a stolen firearm is entered into the National Crime Information Center (NCIC) it remains on that records until it is recovered, and removed from the database.Added: The above response is correct BUT - it does not answer the original question. A stolen firearm will be entered into NCIC IF the complainant is able to supply the firearm's serial number.
call local law enforcement
yes it is
You will have to contact the police to see if it has been reported stolen.
unless you knew it was stolen you are OK. There must be knowledge that you knew it was stolen to procecute you
After you report it to the police, you wait and hope.
You will most likely, almost definitely, be arrested.
Have the police run the serial number.