How long can the police check the text messages?

About a month. How often to check the content of short messages can be decided according to the needs of investigation. Technically, within a certain period of time, the content of short messages (whether sent or received) will be saved to the computer of a company providing communication services, so it is not difficult to find the content of short messages. On the legal level, according to the provisions of Article 148 of the Criminal Procedure Law, after the public security organ files a case, it can take technical investigation measures for crimes endangering national security, terrorist activities, organized crimes of underworld nature, major drug crimes or other crimes that seriously endanger society according to the needs of investigating crimes. Technical reconnaissance measures include electronic monitoring, telephone monitoring, electronic monitoring, secret photography, video recording, mail inspection and other secret special technical means, and naturally short message inquiry can also be carried out.