A wildlife expert claims killing Harambe the gorilla was "the only decision" for the response team at Cincinnati Zoo.
The 17-year-old gorilla was shot dead after a 10-minute incident after a child fell into his enclosure.
The boy, whose name is yet to be confirmed, escaped with only minor injuries.
He is reported to have crawled through a barrier before falling 12 feet into Harambe's pen.
Footage from the incident has been seen online, with many people claiming the gorilla didn't mean to harm the boy.