During criminal detention, family members are generally not allowed to write letters unless they become the defense lawyers of the parties. The meeting and communication between defense lawyers and criminal suspects must be approved by the judicial organs. If a family member hires a lawyer and then wants to communicate with the suspect in his personal capacity, the public security organ will generally not agree.
legal ground
Article 37 of the Criminal Procedure Law
Defense lawyers can meet and correspond with criminal suspects and defendants in custody. Other defenders, with the permission of the people's courts and people's procuratorates, may also meet and correspond with criminal suspects and defendants in custody.