Legal analysis: (1) When investigating and collecting evidence, the defense lawyer must present a special letter of introduction, a power of attorney and a lawyer's practice certificate issued by a law firm to the respondent, and it shall be conducted by two or more people. It may include lawyers from other law firms who are working on this case. (2) When investigating and collecting evidence, the defense lawyer may record and video the whole process with the consent of the respondent. (3) When investigating and collecting evidence, a defense lawyer shall make an investigation record, which shall be signed by investigators, witnesses or representatives of grass-roots organizations, units, judicial organs and other relevant participants. (4) When a defense lawyer investigates and collects evidence, it is best to have witnesses present, but the following persons shall not be used as witnesses in the investigation and collection of evidence.

Legal basis: Article 41 of the Criminal Procedure Law of People's Republic of China (PRC). Defenders have the right to apply to the people's procuratorate and the people's court for the collection of evidence materials to prove the innocence or minor crimes of criminal suspects and defendants collected by public security organs and people's procuratorates in the process of investigation, examination and prosecution.