How should criminal lawyers investigate and collect evidence?

Article 35 of the Criminal Procedure Law stipulates that the defender's responsibility is to put forward materials and opinions to prove that the criminal suspect or defendant is innocent or light, or to reduce or exempt his criminal responsibility according to facts and laws, and to safeguard the legitimate rights and interests of the criminal suspect or defendant. Article 36 From the date when the people's procuratorate examines and prosecutes a case, the defense lawyer may consult, extract and copy the litigation documents and technical appraisal materials of the case, and may meet and correspond with the criminal suspect in custody. Other defenders, with the permission of the People's Procuratorate, may also consult, extract and copy the above-mentioned materials, and meet and correspond with criminal suspects in custody.

Since the people's court accepted the case, the defense lawyer can consult, extract and copy the materials of the alleged criminal facts in this case, and can meet and correspond with the defendant in custody. With the permission of the people's court, other defenders may also consult, extract and copy the above materials, and meet and correspond with the defendant in custody.

Article 37 With the consent of witnesses or other relevant units and individuals, defense lawyers may collect materials related to this case from them, or apply to the people's procuratorate or the people's court to collect and obtain evidence, or apply to the people's court to notify witnesses to testify in court.

With the permission of the people's procuratorate or the people's court, and with the consent of the victim or his close relatives or witnesses provided by the victim, the defense lawyer may collect materials related to the case from them.