Regulations Governing Interview Implementation by the National Immigration Agency, Ministry of the Interior Article 11

Interviews shall be conducted by designated NIA personnel. In principle, an interviewing team shall be formed of two persons, one of whom shall be a Grade 4 or higher junior officer. However, where a senior officer of Grade 6 or higher conducts an interview, the officer may conduct the interview alone.If a person conducting an interview discovers that there is a suspicion of involvement in a crime, the matter shall be handled in accordance with the Code of Criminal Procedure.
中文原文 內政部入出國及移民署實施面談辦法第11條
實施面談人員由移民署指定人員擔任,以二人一組為原則,其中一人應為委任四職等以上人員。
但指定薦任六職等以上人員者,得以一人為之。
實施面談人員發現有涉及犯罪嫌疑情事時,應依刑事訴訟法規定辦理。

English translation for reference only; the Chinese text prevails. Not legal advice.