according to article 156 of the criminal procedure law, after a criminal suspect is arrested, the period of investigation and detention shall not exceed two months. If the case is complicated and the investigation cannot be concluded at the expiration of the time limit, it may be extended for one month with the approval of the people's procuratorate at the next higher level.
for special reasons, if it is not appropriate to extend the trial period for particularly serious and complicated cases, the Supreme People's Procuratorate shall report to the NPC Standing Committee for approval. A criminal suspect may be sentenced to fixed-term imprisonment of not less than 1 years, and if the investigation cannot be concluded after the extension according to the provisions of Article 158 of this Law, it may be extended for another two months with the approval or decision of the people's procuratorate of a province, autonomous region or municipality directly under the Central Government.
Extended information:
The relevant requirements of criminal proceedings stipulate:
1. If the criminal suspect is found to have other important criminal facts during the investigation, the term of detention for investigation shall be recalculated according to the provisions of Article 156 of this Law from the date of discovery.
2. If a criminal suspect does not tell his real name and address and his identity is unknown, his identity shall be investigated, and the period of investigation and detention shall be counted from the day when his identity is ascertained, but the investigation and evidence collection of his criminal acts shall not be stopped. If the facts of the crime are clear, the evidence is true and sufficient, and it is really impossible to find out his identity, he can also sue and try under his self-reported name.
3. Before the investigation of the case is completed, if the defense lawyer makes a request, the investigation organ shall listen to the opinions of the defense lawyer and record them. If a defense lawyer puts forward a written opinion, it shall attach a volume.
Central People's Government-Criminal Procedure Law