Parents Deonne Dickerson and Michelle Gregg have been accused of failing to protect their child.
United States police in the city of Cincinnati on Tuesday said that they're investigating the parents of a four-year-old boy who fell into a gorilla enclosure in the Cincinnati Zoo.
The incident, which resulted in a gorilla named Harambe being shot and killed by zoo officials, sparked public outrage.
Media outlets quoted a spokesperson for the police as saying "The actions of the parents/family that led up to the incident" are being investigated, "and not the operations or safety of the Cincinnati Zoo."
The parents of the boy, Deonne Dickerson and Michelle Gregg, have been accused of failing to protect their child.
People heavily criticised the couple on social media.
Some tweets called for the parents to be held responsible for causing the death of the 17-year-old western lowland gorilla named Harambe, while others called on the public to give their opinions.
Are the parents of the child who fell in the gorilla pen to blame for the gorilla being shot??What do you think?— Jasmine Anastasia (@Miss_Jazziepugh) June 1, 2016
A video was posted on social media showing the child being dragged by the gorilla for 10 minutes.
Many social media users said the gorilla should have been tranquilised instead of killed.
Vetenarian Dr Chris Brown says that a tranquiliser would've taken five minutes to sedate the animal.
In a Facebook post, Brown said, "The zoo staff acted on an existing protocol. Clearly we wouldn't even be discussing the tragedy if the four-year-old had been properly supervised."
Brown also shared a video showing how a similar case in 2007 in which a gorilla protected a child who slipped and fell 4 metres into the enclosure.
Another video of the incident has circulated and sparked a fresh debate on what happened.
In the video, Harambe appeared to be protecting the boy and also held his hands.
But, Gregg thanked zookeepers for shooting the animal.
The Zoo insisted that shooting the 450lb animal was the right decision as other options were too risky.
In a Facebook post, Gregg wrote, "I am thankful that the right people were in the right place today. Accidents happen. 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."