legal ground
People's Republic of China (PRC) Lawyers Law Article 37 The personal rights of lawyers in their practice activities are inviolable.
Lawyers' opinions on agency and defense expressed in court are not subject to legal investigation. Except for statements that endanger national security, maliciously slander others, and seriously disrupt court order.
If a lawyer is detained or arrested according to law for participating in litigation activities on suspicion of committing a crime, the detention and arrest organ shall notify the lawyer's family, his law firm and lawyers' association within 24 hours after the detention and arrest.