Moments later, the 17-year-old gorilla was fatally shot by zoo staff in a bid to protect the boy after falling 12 feet into the enclosure.
However eyewitnesses have claimed that the gorilla was showing no aggressive behaviour towards the boy.
It is claimed that screams from those watching the unfolding situation panicked the animal, causing him to drag the child at a quick speed across the water.
And in this latest video from the dramatic scene, the boy is seen sat calmly next to the massive animal.
In one moment, the gorilla even appears to wrap his arms around the boy.
At one point the boy and gorilla even appear to briefly hold hands.
Brittany Nicely was at the zoo with her children when she witnessed the incident.
Writing on Facebook after the incident, she said: "R.I.P Harambe so so sad.
"Witnessing this situation and hearing them shoot him has been one of the most horrific things I have ever been a part of.
"My thoughts and prayers go out to all of the staff at the Cincinnati Zoo & Botanical Garden and the people who witnessed it.
"Also sending prayers for a speedy recovery of the little boy!"
Mrs Nicely has also claimed that the gorilla was not being aggressive towards the boy.
"I tried to prevent it," she added. "I tried to grab him and I just couldn’t get to him fast enough.
"What the first responders saw, I’m just not sure... They said he was violently throwing the child around, which seems crazy to me.
"They have a picture of the boy sitting in front of the gorilla moments before they shot him."