Legal basis: Criminal Procedure Law of People's Republic of China (PRC).
Article 52 People's courts, people's procuratorates and public security organs have the right to collect and obtain evidence from relevant units and individuals. The relevant units and individuals shall truthfully provide evidence.
Evidence materials such as physical evidence, documentary evidence, audio-visual materials and electronic data collected by administrative organs in the process of administrative law enforcement and case investigation can be used as evidence in criminal proceedings.
Evidence involving state secrets, commercial secrets and personal privacy shall be kept confidential.
Whoever forges, conceals or destroys evidence, and whoever the evidence belongs to, will be investigated by law.
Article 59 The testimony of a witness must be cross-examined and verified by the public prosecutor, the victim, the defendant and the defender in court before it can be used as the basis for finalizing the case. If the court finds that a witness intentionally perjures or conceals criminal evidence, it shall deal with it according to law.
Article 60 Anyone who knows the circumstances of a case has the obligation to testify.
A person who is physically and mentally defective or young, can't distinguish right from wrong and can't express correctly, can't be a witness.