The family members of the criminal detainee shall learn the facts of the suspected crime from the public security organ or procuratorate handling the case at the first time.
 Have the right to know the place of custody from the case handling organ. According to the law, the summoning and compulsory summoning shall not exceed 12 hours, and the criminal suspect shall not be detained in disguised form by summoning and compulsory summoning. After detaining a person, the public security organ shall, within 24 hours, notify the detainee's family members or the unit to which he belongs of the reason for detention and the place of custody, except in cases that hinder investigation or cannot be notified. If there is no notice of detention after being detained for dozens of days, it is usually the case that the prisoner is arrested in another place. Usually, in this case, the family members of the suspect can directly call the local police station to find out whether there is a notice of detention, so as to know the place and reason of the prisoner's detention. If the family members confirm that their relatives are detained or arrested and also know the place of detention, they can timely hire lawyers to meet in the detention center to protect the legitimate rights and interests of the parties.
 Legal basis
 The organ that decides to detain in accordance with Article 64 of the Criminal Procedure Law shall notify the detainee's family members or his unit of the reason for detention and the place of detention within 24 hours after detention, except for those who hinder investigation or cannot be notified. The circumstances hindering investigation include: other joint criminal suspects who are likely to hide, destroy, abandon or forge evidence after hearing the news; They may collude with each other to form an offensive defensive alliance; Other crimes that need to be verified and corresponding measures have not been taken, etc. However, after the above circumstances are eliminated, the detainee's family member or his unit shall be notified immediately. If no notice is given within 24 hours, the reasons shall be indicated in the notice of detention. The circumstances that cannot be notified include: the detainee does not tell the true name and address; The detainee has no family or work unit, etc.