The Regulation Governing the Handling of Investigation Procedures for Civil and Public Aircraft Occurrence Article 8

The TTSB may terminate an ongoing investigation after deliberating its feasibility but shall specify the reasons for such termination.
中文原文 民用航空器及公務航空器重大飛航事故調查作業處理規則第8條
運安會經審度調查之可行性後,得於重大飛航事故調查進行時中止調查,但應述明理由。

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