Legal analysis: criminal detention for 37 days, the police notice to sign, usually the procuratorate approved the arrest. When arresting a person, the public security organ must produce an arrest warrant and order the arrested person to sign the arrest warrant and press his fingerprint. If the investigator refuses to sign or fingerprint, the investigator shall indicate it.

Legal basis: Article 91 of the Criminal Procedure Law of People's Republic of China (PRC). If the public security organ deems it necessary to arrest the detained person, it shall submit it to the people's procuratorate for examination and approval within three days after detention. Under special circumstances, the approval time can be extended by one to four days.

For major suspects who commit crimes on the run, commit crimes many times or commit crimes in collusion, the time for submitting for examination and approval may be extended to 30 days.