Write an article based on this "Research your state's law. Gather information about the incident. File your report with the police department. Cooperate with any further investigation."
Since police only investigate complaints that violate state law, studying the elements of criminal fraud in your state can help you figure out what information you need to file a complete report.  Although the specific requirements and wording vary among states, criminal fraud typically includes the same basic elements. Generally, the person must misrepresent an important fact knowing that what they're saying is false, with the intent to deceive you into giving them money or property.  Also keep in mind that you must have suffered some actual loss to be a victim of fraud. If you see a listing and recognize it as fraudulent, you can still report it – but the person typically can't be found guilty of fraud unless someone has actually fallen for their scam. However, they possibly could be prosecuted for attempted fraud. You will need information about the other user and details about the transaction so the police are able to conduct an investigation.  Using your knowledge from your legal research, focus on any documents or statements from the user that might indicate a criminal intent to defraud you. Keep in mind you're probably not going to find anything that proves the person knew the things they were telling you were false. You don't need to do any extensive detective work – rather, you should leave this work up to the police. Just focus on making sure you get the details about the transaction down along with any correspondence you've had with the user. Once you have all your information together, call or stop by the nearest police precinct to submit your report.  Keep in mind that typically the police in the town and state where the perpetrator is located will be primarily responsible for investigating the activity. However, if you submit your report to your local authorities they will be able to transfer information if necessary. Some police departments have online forms you can fill out to submit a report. You can find the appropriate contact information for your local law enforcement agency by visiting http://www.usacops.com. In your report, include a detailed chronological description of the events that took place. If you can reconstruct a timeline from the day you first encountered the listing until the moment you realized you were a victim of fraud, this can be helpful to the police as they investigate your report. When you file your report, ask for a reference number and a copy of the official report for your records. You may need them to add support to other reports or complaints you file. As the police investigate the activity, you may be contacted for additional information.  Additionally, if you have the reference number for your case, you can call the police department to check on its status.  Police have discretion on whether to pursue claims, and how long to pursue them. If losses are minimal and the police have very little information to go on, they may opt not to extend the investigation.