How to write letters to detainees in detention centers

If it's not a large detention center and you don't know the number, just write your name directly. If it is a large detention center, it will be a little troublesome to communicate without knowing the number of people and room numbers. However, not all detainees are numbered, but only for individual duty crimes (such as corrupt officials) to prevent collusion. Management methods vary from place to place.

The law provides that:

Article 28 "Regulations on Detention Center" Criminals may communicate and meet with their close relatives with the consent of the case-handling organ and the approval of the public security organ during their detention.