Lawyers can't violate the prohibition when meeting, and some main norms can be listed:
1, can't pass any clues about the case for the criminal suspect or defendant, including clues to expose the crime;
2. You can't use your own mobile phone to let criminal suspects and defendants contact the outside world;
3. You can't collude with criminal suspects and defendants in various ways, and you can't transmit information suspected of collusion by means of body language, notes, palm prints, etc.
4. You can't bring non-lawyers to the meeting, and you can't bring criminal suspects and defendants' families to the meeting;
5. Can't pass on all kinds of information and articles prohibited by the supervision place to criminal suspects and defendants;
6. Prevent criminal suspects and defendants from escaping from the supervision place by meeting.
To sum up, lawyers must obtain the consent of witnesses when meeting witnesses, and also the consent of public prosecution and judicial organs under legal circumstances. According to the law, if a lawyer investigates and collects evidence on his own, he may, with the lawyer's practice certificate and the certificate of the law firm, investigate the situation related to undertaking legal affairs with the relevant units or individuals.
Legal basis: Article 35 of the Lawyers Law of People's Republic of China (PRC).
The entrusted lawyer may, according to the needs of the case, 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.
If a lawyer investigates and collects evidence by himself, he may, with the lawyer's practice certificate and the certificate of the law firm, investigate the situation related to undertaking legal affairs with the relevant units or individuals.