"The mother looked around and ran to the wall and said, 'Oh my God, that's my son!' " an onlooker tells PEOPLE
Credit: Kim O'Connor

An eyewitness of a 4-year-old’s fall into the gorilla enclosure at the Cincinnati Zoo on Saturday says that the boy told his mother he “wanted to swim with the gorilla” as she was preparing to leave the exhibit with a female companion and multiple young children.

“People around me were talking about how big the gorilla was, calling him King Kong, and I heard him say ‘I wanna go!’ and the mom was like, ‘No, you’re not!’ ” Kim O’Connor, who filmed the incident, tells PEOPLE. “She was putting kids in the strollers – there were four or five kids total – and getting ready to leave the exhibit. She didn’t have him by the hand, and at one point, he must have been behind her, out of sight.”

She adds, “I don’t think in her wildest imagination she thought he would actually go back and do that.”

The 17-year-old animal named Harambe was shot dead by zookeepers after he grabbed the little boy and dragged him around the exhibit.

O’Connor says the mother, who has been identified in reports as Little Blossoms Academy Preschool administrator Michelle Gregg, didn’t realize it was her own son who had fallen into the enclosure at first.

“All of a sudden, I heard a splash and someone yelled, ‘Oh my God, there’s a kid in there!’ ” O’Connor says. “Kids, men, women, everyone started screaming and then the mother looked around and ran to the wall and said, ‘Oh my God, that’s my son!’ ”

Another onlooker, Deidre Lykins, said the little boy “literally flopped over the railing,” in a Facebook post.

She added, “I assumed the woman next to me was the mother, getting ready to grab him until she says, ‘Whose kid is this?’ None of us actually thought he’d go over the nearly 15-foot drop, but he was crawling so fast through the bushes before myself or husband could grab him, he went over!”

The 450-pound male gorilla crept out of a cave when he heard the commotion.

“He approached the entrance of the cave and as people screamed, his manner was aggressive, he was huffing and looking rapidly at the crowd and making a snorting noise,” says O’Connor. “That’s when he pulled the boy to the end of the moat.”

In the video that O’Connor filmed, a woman’s voice can be heard saying, ‘Calm down, Isaiah! Mommy loves you.”

O’Connor says she was filming the terrifying incident with help from her niece – but turned the camera off when Harambe pulled the boy onto the cement portion of the exhibit.

“I was frozen in fear, it was too traumatic to be on camera,” she says. “What you don’t see is the way he pulled the boy up the wall. He was treating the little boy like a Raggedy Ann doll in his grip.”

“He moved him around side to side, behind him. He scooped him up to his belly sitting down. The boy tried to scoot away and he pulled him right back in,” says O’Connor. “Something spooked [the animal] and he dragged the boy across the cement exhibit to another cover area where he couldn’t get away. He had the boy underneath him between his legs.”

O’Connor says she grabbed Gregg, telling her she needed to follow the zookeepers.

“She stopped and turned around and she was torn between running with the security guard and leaving her other children who were standing there,” she says. “In that moment, she had the mindset to be torn.”

After that, O’Connor left the vicinity.

She says her back was turned as she ran away from the gorilla exhibit. That was when she heard the gunshot that killed Harambe.

Gregg defended herself in a now-deleted Facebook post, writing: “God protected my child until the authorities were able to get to him. My son is safe and was able to walk away with a concussion and a few scrapes no broken bones or internal injuries.”

Gregg continued, “As a society we are quick to judge how a parent could take their eyes off of their child and if anyone knows me I keep a tight watch on my kids. Accidents happen ”

A spokeswoman for the family released a statement from the family thanking the Cincinnati Zoo staff for their “quick action.”

“We are so thankful to the Lord that our child is safe. He is home and doing just fine We know that this was a very difficult decision for them, and that they are grieving the loss of their gorilla,” said the family.

Cincinnati Zoo Director Thane Maynard, who says the zoo will not be pressing charges agains the family, defended the decision to shoot and kill Harambe during a press conference on Monday.

“The idea of waiting and shooting it with a hypodermic was not a good idea. That would have definitely created alarm in the male gorilla. When you dart an animal, anesthetic doesn’t work in one second, it works over a period of a few minutes to 10 minutes. The risk was due to the power of that animal.”

He adds, “Everyone should keep hold of their kids. Here, the mall, the schoolyard. But the zoo is a safe place.”

A vigil for Harambe was held near the front entrance to the zoo on Monday afternoon and people have been leaving flowers, notes and pictures in memory of the animal around a gorilla statue on the premises.

Animal activists created an online petition requiring 300,000 signatures called “Justice for Harambe,” that will be used to encourage the Cincinnati Zoo, Child Protection Services and Cincinnati Police Department to hold the parents accountable for Harambe’s death.