Enforcement Rules of the Control Act Article 26

If it is determined that the details of a case under investigation by members of the Control Yuan are related or the same, a request for approval shall be submitted to the president of the Control Yuan and the investigation shall be conducted by the member who was first to investigate. In special cases, the president of the Control Yuan may request a joint decision by the investigating members.
中文原文 監察法施行細則第26條
監察委員調查中之案件,如發現彼此案情相關連或同一者,應簽請院長核定並由最先調查之委員調查;但特殊案件,院長亦得商請調查委員共同決定之。

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