National Police Agency Organization Act, Ministry of the Interior Article 7

To fulfill duty requirements, the Agency may post officers overseas upon approval by the Executive Yuan pursuant to the Organization Act of Diplomatic Missions.
中文原文 內政部警政署組織法第7條
本署為應業務需要,得報請行政院核准,派員駐境外辦事,並依駐外機構組織通則規定辦理。

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