The investigation into an offense against this Act shall be conducted by a police agency as soon as the offense becomes known to the police whether because it has been discovered by police, being tipped off by a citizen, the offender has turned themselves in or because of other circumstances.

Items that are admissible as evidence or shall be confiscated shall be kept properly. If a court decides not to confiscate an item in custody, it shall be returned to its owner, possessor, or custodian. In the absence of a owner, possessor, or custodian, it shall be handled in accordance with applicable laws.

The police shall notify a suspect and may notify a witness or a related party to investigate an offense against this Act.
The notification letter described in the preceding paragraph shall specify the following information:
1. The name, gender, date of birth, registered residency, residency or temporary residency of the person being notified.
2. The reason for the notification.
3. The date, time when and place where the suspect should appear.
4. If failing to appear without justifiable reasons, the decision of punishment may be made directly.
5. The name of the agency which made the notification.
In cases that the name of the person being notified is unknown or other circumstances under which is considered necessary, their distinguishable characteristics shall be recorded, while the date of birth and permanent and current residency may be omitted if they are unknown.
Before interrogating a suspect about their name, date of birth, permanent or current residency, the investigator should tell them the reasons for the notification first and give them an opportunity to plead to the charge.
The suspect may authorize a legal representative to represent them during a trial or investigation. However, the court or police authority may demand the suspect to be present in person when it is considered necessary.

Police may restrain a person who is caught red-handed in the commission of an offense against this Act and notify them to report to a police agency on the scene. Police may take the person back to the police agency by force. Nonetheless, the preceding article may apply if the offender’s name, residency or temporary residency is known to the police and the possibility of fleeing is slim.