As criminals flee abroad after committing crimes or being convicted, there are many effective practices of international cooperation in criminal matters regarding overseas arrest modes, proposing the most formal extradition request (by requesting state), expelling or repatriating via immigration measures (of the requested state), or even arresting criminals without the other country’s consent, etc.
All these efforts are to return these criminals back to the country which has the jurisdiction over the crimes to pursue prosecution, trial or execution of sentences against these criminals.
No matter returning the criminals to the requesting country via extradition or deportation, while handing over the perpetrators, the freedom of the perpetrators was therefore constrained. Consequently whether the terms of overseas detention or constrain can be deducted from their subsequent imprisonment causes controversial human right issues along with international cooperation. The Court has not yet delivered consistent opinions, so the need for further academic research therefore presents.
This paper first tries to define various international cooperation methods such as extradition, expulsion and deportation and probes their legal features. As the deduction policies of overseas detention period, this paper explores several international regulations and legislations regarding this issue and finally, analyzes recent opinions regarding international immigration cooperation and cross-strait mutual legal assistance delivered by the Supreme Court in 2012 and 2015 respectively. Therefore, expecting this research on overseas detention issue will be the first step for further study.