1. Find out the reason: contact the bank to find out the specific reason, freezing unit and time limit of the card, and whether it can continue to be frozen;

2. Cooperate with the investigation: provide necessary supporting documents and materials to the public security department to help verify whether the account is related to the case;

3. Preparation materials: prepare identity certificates, transaction records, work certificates and other related materials to prove the legality of account activities;

4. Apply for thawing: submit a written application and supporting documents to the freezing authority to request thawing;

5. Legal consultation: if necessary, consult a lawyer or legal adviser for professional advice and help.

Security protection measures for bank cards:

1. Change the bank card password regularly: It is recommended that bank card holders change their bank card passwords regularly to enhance account security;

2. Start SMS notification service: through the SMS notification service provided by the bank, monitor the transaction dynamics of the account in real time and find abnormal situations in time;

3. Restrict large-value transactions: setting a single or daily transaction limit for bank cards can effectively prevent large-value capital losses after the cards are lost or stolen;

4. Use bank card security tools: install the mobile banking APP recommended by the bank or use hardware tokens to provide double verification for online banking transactions;

5. Keep the bank card information properly: avoid revealing the bank card and its information to others at will, especially the card number, expiration date and security code;

6. Report the loss to the police in time: once the bank card is found to be lost or there is an unauthorized transaction, you should immediately report the loss to the bank and report it to the police.

To sum up, when the bank card is frozen by the public security, it is necessary to contact the bank to understand the reasons for freezing, provide the public security department with necessary supporting documents and materials, prepare relevant materials to prove the legality of account activities, then submit the application and supporting documents to the freezing authority, and finally consult a lawyer or legal adviser and seek professional advice and help if necessary.

Legal basis:

Procedures for handling criminal cases by public security organs

Article 243

The time limit for freezing deposits, remittances, securities trading settlement funds, futures deposits and other property is six months. The time limit for freezing deposits, remittances and other property shall not exceed six months.