Therefore, the evidence collected through the above illegal procedure is inadmissible and thus the defendant should be pronounced not guilty. However, the court below which found the defendant guilty erred by misapprehending the facts or by misapprehending the legal principles, which affected the conclusion of the judgment.

2. Determination

A. In a case where it is clearly proved by objective circumstances that an investigator of the relevant legal doctrine knew that he/she could refuse to accompany a suspect prior to accompanying the suspect while accompanying the investigative agency, etc. in the course of the investigation, or where it is acknowledged that the suspect, at any time, could freely leave the accompanying place or could leave the accompanying place, etc., and that the accompanying was carried out by the investigative agency, etc., the legality of accompanying is recognized.

In addition, the determination of the voluntariness in such voluntary behavior should be based on objective circumstances, comprehensively taking into account various circumstances, such as the time and place of accompanying, the method of accompanying, the existence of intent to refuse accompanying, the method of investigation after accompanying, and the existence of the intention to leave.

On the other hand, in light of the provisions of Article 44 (2) of the Road Traffic Act, in case where there are reasonable grounds to recognize that a driver has driven a motor vehicle under the influence of alcohol and it is necessary to confirm whether a driver has driven a motor vehicle under the influence of alcohol, a police officer cannot confirm whether a driver has driven a motor vehicle under the influence of alcohol by means of an ex post facto measurement unless it is clear that a police officer cannot confirm whether a driver has driven a motor vehicle under the influence of alcohol, and in