1, investigated and collected by the parties and their agents ad litem;
2. The lawyer holds a lawyer's power of attorney to investigate and collect evidence;
3, the parties apply to the people's court for investigation and evidence collection;
4. The people's courts conduct investigations ex officio.
legal ground
Article 52 of the Criminal Procedure Law stipulates that judges, prosecutors and investigators must collect all kinds of evidence that can prove the guilt or innocence of criminal suspects and defendants and the seriousness of the crime in accordance with legal procedures. It is strictly forbidden to extort confessions by torture and collect evidence by threats, enticements, deception or other illegal methods, and no one may be forced to prove his guilt. It is necessary to ensure that all citizens who are related to or know the case have the conditions to provide evidence objectively and fully, and they can be hired to assist in the investigation except in special circumstances.