Legal basis: "People's Republic of China Criminal Procedure Law"
Article 82 A public security organ may detain a flagrante delicto or a major suspect in advance under any of the following circumstances: (1) He is preparing to commit a crime, commits a crime or is found immediately after committing a crime;
(2) The victim or the person present identified him as a criminal;
(3) evidence of a crime is found around or at his residence; (four) attempted suicide, escape or escape after the crime; (5) It is possible to destroy, forge evidence or collude with others; (six) do not speak the real name and address, and the identity is unknown; (7) Being seriously suspected of committing crimes on the run, committing crimes for many times, or committing crimes in association.
article 85 if a public security organ detains a person, it must produce a detention permit. After detention, it shall be immediately sent to the detention center for custody, and shall not exceed twenty-four hours at the latest. The family members of the detained person shall be notified within 24 hours after detention, except in cases where it is impossible to notify or the notification of crimes suspected of endangering national security or terrorist activities may hinder the investigation. As soon as the circumstances that hinder the investigation disappear, the families of the detainees should be informed immediately.
article 91 if a public security organ deems it necessary to arrest a detainee, it shall submit it to the people's procuratorate for examination and approval within three days after detention. Under special circumstances, the time for submitting for examination and approval may be extended by 1 to 4 days. For major suspects who commit crimes on the run, recidivism or gang crimes, the time limit for submitting for examination and arrest may be extended to 3 days. The people's procuratorate shall, within seven days from the date of receiving approval of arrest 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 release the criminal suspect immediately after receiving the notice and inform the people's procuratorate of the implementation in time. For those who need to continue the investigation and meet the conditions of obtaining a bail pending trial or residential surveillance, they shall be released on bail pending trial or residential surveillance according to law.