Extortion is a felony crime that involves taking someone's money or property by threat of harm. The perpetrator may threaten to damage your property, injure you or even harm your reputation. For example, if you refuse to loan a friend your car and he threatens to break its windows if you don't do what he wants, this would generally constitute extortion. Likewise, if an ex threatens to reveal embarrassing pictures or videos of you unless you pay him money, that's extortion.
Extortion can fall under both state and federal laws. You can report this type of activity to your local police department or the FBI, depending on the crime. If you are dealing with a private matter, such as an old friend who is trying to blackmail you, local police may be able to handle this matter. To report it, you generally need to speak with an officer and file a police report. The police will typically interview you and ask for the times, places and details of the possible extortion. If you are dealing with extortion on a larger scale -- such a matter that crosses state lines or involves organized crime -- you may need to contact your closest FBI branch office. An agent will interview you in a similar manner as the local police. Consulting an attorney or your local prosecutor's office can help you determine the best agency to handle your case.