It would appear that you’ve tried, convicted, and sentenced a dead 17 year old who is unable to give his side of what happened. That is sad.
SoldierDad where is the additional evidence going to come from? There is none. So the kind of investigation you are seeking will be nothing but political circus (to further the agenda of crooks and race-baiters)
It will not bring the dead boy back, nor likely to put the man that shot him in jail. Elongating this situation tho is sure to cause trouble as I see it is here on this thread.
Best that it be laid to rest.