legal ground
Article 143rd of the Provisions on Procedures of Public Security Organs for Handling Criminal Cases
When an arrest is made, an arrest warrant must be produced, and the arrested person must be ordered to sign the arrest warrant and press his fingerprints. If the investigator refuses to sign or fingerprint, the investigator shall indicate it. After the arrest, the arrested person shall be immediately sent to the detention center for custody.
No fewer than two investigators shall carry out the arrest.