After 37 days in criminal detention, no one was released and no arrest warrant was received.

Legal analysis: criminal detention is decided by the public security organ, and the longest period is no more than 37 days. The public security organ must report to the procuratorate for approval of arrest before this. If the arrest is not approved at the expiration of the time limit, the public security organ must lift the detention and change compulsory measures such as bail pending trial and residential surveillance. After the change, the public security organ may continue to investigate, monitor residence for no more than six months, and obtain bail for no more than one year. After the expiration, it will not be accepted in principle.

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. The people's procuratorate shall, within seven days after receiving the approval letter from the public security organ, make a decision on whether to approve or disapprove the arrest. If the people's procuratorate does not approve the arrest, the public security organ shall immediately release it after receiving the notice and promptly notify the people's procuratorate to execute it. Those who need to continue the investigation and meet the conditions of obtaining a guarantor pending trial or residential surveillance shall be granted a guarantor pending trial or residential surveillance according to law.