The public security bureau can inquire how long it will take to file a case by SMS.

The police can check the text messages within six months. The public security bureau can find short messages, but it can't just check them. According to the law, the freedom and privacy of communication of China people and citizens are protected by law. Except for the needs of national security or criminal investigation, public security organs and procuratorial organs shall inspect communications in accordance with the procedures prescribed by law.

legal ground

Article 40 of the Constitution

People's Republic of China (PRC) citizens' freedom and privacy of communication are protected by law. When public security organs and procuratorial organs check communication according to the procedures prescribed by law, no organization or individual may infringe upon citizens' freedom and privacy of communication for any reason, except for the needs of national security or criminal investigation.