Contact Law Enforcement Authorities
If you receive threats that need immediate assistance, you should save the e-mail(s) and contact your local authorities or 911.
To report other threatening, inappropriate, or unwanted e-mails, you can find contact information for the appropriate law enforcement officers at The National Association of Attorneys General (NAAG) Web site. The NAAG has assembled a "Computer Crime Point-of-Contact" list of prosecutors and investigators from state and local law enforcement agencies that specialize in computer related crimes.
The local police may choose to pass your complaint on to the state and federal authorities. While local law enforcement should be the first place you contact for help, another option is to contact your local FBI field office directly.
If you receive email messages from someone wanting to use your bank account so they can transfer several million dollars to you, you should be aware that this is a scam. More information is available from the United States Secret Service, at http://www.treas.gov/usss/financial_crimes.shtml#Nigerian.