Call your bank. Your bank may use sophisticated software to detect fraud on debit cards and a representative may have called you to inquire about potential fraud. In the off-chance that you suspect a fraud is perpetrated, calling your bank will put a "freeze" on the card. This means it cannot be used by the criminal, and it limits the amount of money they can make from the theft.
Gather information. While you are on the phone with the bank, whether they have called you or you have called them, ask where and when the card was used. Tell your bank which transactions are legitimate and which are fraudulent. Ask if your PIN was used in any of the transactions. In cases where items were purchased, ask if they know whether the card was swiped or whether the number was simply entered into the machine.
Ask if the bank has a specific incident number you or the police can reference when conducting follow-up calls. Also, ask for a direct number that the police can call to ask their own questions about the fraud.
Contact the police department where you live. Start by calling the non-emergency number. Inform the department that you are a victim of identity theft. Ask to file a police report. They may ask you to report to the station to file the report. Some departments allow complainants to make reports over the phone.
Provide the police with all the information you have gathered, including contact information for your bank. The bank may be able to provide information to the police that it cannot provide to you. The police may ask you for more information. They may ask you to file additional complaints in jurisdictions where the fraudulent transactions occurred. Follow their instructions.
Follow up. Police departments rarely have the resources to investigate individual debit card frauds. The transactions are too far flung, and there simply too many instances of theft. But reporting fraud can give police leads on complicated fraud rings. Gathering copies of the police reports, likewise, can help you fight damage to your credit report, especially if fraudsters have opened accounts in your name.