The insignificant nobody me will attempt to help more understand the issue better, & will use simple expressions rather than complex legal terms that will only confuse the ordinary laymen.
1. Mr Rajapaksa is NOT a war criminal, a prisoner of war, or even a convicted criminal. In USA, a Human is innocent till proven guilty by a Court of Law, not just by anyone. Some other nations treat the opposite.
However, Mr Rajapaksa is a Sri Lanka citizen & Spore has NO jurisdiction on the Rule of Law in Sri Lanka, NOR does Sri Lanka has jurisdiction on the Rule of Law in Singapore. As far as we know, without prejudice, Mr Rajapaksa is NOT convicted of any crime, nor found guilty of any crime in Sri Lanka, or had any extradition papers served by Sri Lanka representative govt to the Spore govt, & is still a FREE citizen as well as a former Head of State & accorded his full rights as a fellow Human.
2. While you & I limitedly know what he had done to Sri Lanka, so too Human Rights group NGOs, Singapore is a Rule of Law Nation. It abides by international rule & Geneva conventions, so too MUST legal due process be followed through, least any other Human or nation would scream unfairness & lack of justice, as there WILL be many sides of disagreement to allegations. Thus, each MUST allow due process & judicial procedural norms be followed. It will not be over night & it will take time, sometimes even years.
3. Mr Rajapaksa has only a temporary visa from the Spore govt. As he is not a CONVICTED criminal, he is free to stay till his visa expires within weeks, or extended upon approval by our govt should he need the time to resolve legal issues with the representatives of Sri Lanka govt & the People of Sri Lanka, as well as the International community.
I understand that by this post, there will be some whom will not be satisfied, but the reality is that a eye for an eye will only leave the whole world blind. Let Justice & the Rule of Law takes its course will be better solution, for justice to be served than pure blind vengeance. Each must answer for their actions to the many.
