Fresno poet Mai Der Vang looks back on a dark chapter of history in her new collection “Yellow Rain.” Hmong refugees fleeing Laos at the end of the Vietnam war reported being attacked with chemical and biological weapons that led to thousands of deaths, but American scientists dismissed refugee accounts, claiming that the mysterious substance raining down on them was the feces of honeybees. Through exhaustive research of once classified documents, Vang reveals the truth of what happened, giving voice to the victims of the attacks. Valley Edition Host Kathleen Schock spoke to Vang about how she uncovered their forgotten stories.