A leading war crimes lawyer tells Channel 4 News the  video apparently showing men taking part in executions in Sri Lanka is  "astonishing evidence" and the United Nations must act.                                         Last week, Channel 4 News screened new footage showing an alleged massacre of Tamil prisoners in Sri Lanka.
          New evidence has since emerged over the possible identities of one of the victims as well as on which soldiers may be responsible. The video has been sent to the United   Nations panel which is currently investigating whether to hold an   international inquiry on what happened during the 26-year war in Sri   Lanka.
          Channel 4 News spoke to war crimes lawyer Julian Knowles of Matrix Chambers about the video and what could happen next.
          Can I ask you what your initial view is of what this  video, what  we've learned from evidence contained in it, what it says  to you about  possible war crimes? 
          What you've got here is clear evidence of the execution of  unarmed  combatants or civilians. It doesn't matter which they are,  they're both  prohibited under the Geneva Convention and they are both ranked as what we call a grave breach of the Geneva Convention so they are crimes in international law.
          And whether these are combatants or whether they're  civilians, their  hands are tied, they're blindfolded, there's no  evidence of any weapons,  so we clearly have executions here which are a  crime in international  law and one of the most serious crimes.
          And does the fact that we now know pretty much  exactly when it  happened and roughly the location, does that have a  bearing on a  possible future trial?
          The evidence that you've uncovered with this video, and what  this  video shows, is absolutely crucial in the forensic process  because it  allows you to identify the troops on the ground, the unit  which they are  from, their local commanders and the higher level  commanders. Because  if you know the region, the Sri Lankan government  will know what troops  it had and at what time. So because you know the  date and because you  know pretty precisely the location, the Sri Lankan  government, if it had  the will, would be able to identify who is  responsible for these  executions and that would obviously be crucial in  any trial, if you want  to put on trial both the soldiers who actually  pull the trigger and the  commanders who gave them the order to do so.
http://www.channel4.com/news/sri-lanka-video-is-astonishing-evidence