Not to mention that if you make the call and it turns out to be nothing, your credibility is gone for future calls where your information COULD be the difference between life and death.
Don't cry wolf on a rumor.
How many times do you think you will ever need to call? I have never placed a call, neither has anyone in my family. Most of America will never have a reason to call.
I would place a call with this information. Let them (FBI, Homeland,...) decide if they want to follow up or not.
As for me, I will be having as little contact as possible mostly because contact with them makes my blood pressure go up and makes my head hurt!