Video from the moments after a 4-year-old boy fell into a gorilla exhibit at the Cincinnati Zoo shows one of the gorillas standing over the boy in a shallow moat.
Frantic screaming can be heard in the background, including a woman yelling "mommy's right here" and "mommy loves you."
Video taken by zoo visitors Saturday shows the 17-year-old gorilla grab at the boy before dragging him.
Zoo officials say its special animal response team shot and killed the gorilla 10 minutes after the boy fell because they felt his life was in danger.
Firefighters then rescued the boy who was in a hospital and is expected to recover.
One witness says she tried to grab the boy before he fell after seeing him in bushes beyond a fence around the exhibit.