A 400-pound gorilla was shot to death on Saturday to save the life of a 4-year-old boy who fell into the animal's enclosure at the Cincinnati Zoo & Botanical Garden.

Zoo visitor Kimberly Ann Perkins O'Connor heard the boy jokingly tell his mother about going into the water below.

The toddler managed to climb through a barrier and fall roughly 15 feet into the enclosed habitat of the 17-year-old western lowland gorilla named Harambe.

The crowd's screams, however, seemed to have drawn the gorilla's attention to the boy. In the beginning, it appeared as if Harambe was trying to assist the boy in standing up. The animal even pulled his pants up.

But the growing pandemonium may have agitated the gorilla who then tossed the 4-year-old into one corner. At this point, O'Connor started to capture the horrifying moments that came next.

For a few moments, Harambe had the boy locked in one corner, shielding him from view, until the gorilla dragged the boy by the foot across the wet enclosure.

The terrifying scene at the zoo ended in the death of Harambe. According to Cincinnati Zoo Director Thane Maynard, shooting down the gorilla was a "tough choice."

Justice For Harambe

People hold opposing views on what happened at the Cincinnati Zoo that day. Some people think that shooting down Harambe wasn't necessary and that, at some point, the gorilla seemed to be protecting the child who fell into his enclosure.

"Unfortunately, it was a bad situation where a 4-year-old didn't have the attention of his mother for seconds. I don't think it was as easy as standing up and falling in. He actually had to climb under something, through some bushes and then into the moat," said O'Connor who left the scene just before the shooting took place.

Other people also criticize the Cincinnati Zoo over the use of excessive force. Protesters conducted a demonstration outside the zoo premises on Sunday, calling for a boycott.

Some critics say the toddler's parents should face criminal liability for the killing of a critically endangered species. An existing online petition has managed to get more than 80,000 signatures in less than a day.