I know who killed your father. Just as commonly believed, they were soldiers, following the edict of a powerful general in cohorts with the Marcoses. But the actual triggerman was never jailed. He was in too deep with a high-ranking official, and those the president freed yesterday were just fall guys.
I don't know if it will help you any. But the triggerman, last I heard has died already. He lived a sad, violent life and had it worse than whatever jail had in store for him originally. God takes care of His own, and he has exacted vengeance for you and your family already.
I hope you try to be at peace.