http://www.ic3.gov/default.aspx

If they receive enough complaints concerning the same person, I would think the chances of them looking into it are greater.

The IC3 accepts online Internet crime complaints from either the actual victim or from a third party to the complainant. We can best process your complaint if we receive accurate and complete information from you. Therefore, we request that you provide the following information when filing a complaint:

• Your name
• Your mailing address
• Your telephone number
• The name, address, telephone number, and Web address, if available, of the individual or organization you believe defrauded you.
• Specific details on how, why, and when you believe you were defrauded.
• Any other relevant information you believe is necessary to support your complaint.