(CNN) The family of a boy who entered a Cincinnati Zoo gorilla's enclosure last weekend -- spurring zoo officials to shoot and kill the animal -- will be the focus of an investigation into the incident, Cincinnati police said Tuesday.

The 3-year-old boy was dragged across a moat by the 450-pound gorilla on Saturday. After a 10-minute encounter, Cincinnati Zoo officials shot and killed the beloved and endangered gorilla, named Harambe. The boy was not seriously injured.

Cincinnati police said Tuesday that their review "is only regarding the actions of the parents/family that led up to the incident and not related to the operation or safety of the Cincinnati Zoo."

"After the review, we will determine if charges need to be brought forward," police spokeswoman Tiffaney Hardy said. "If it is determined charges need to be brought forward, we would then discuss it with the Hamilton County prosecutor's office."

Authorities have said the boy's mother was with the child at the time he slipped past a fence and tumbled into the moat.

Julie Wilson, spokeswoman for the prosecutor's office, declined to say how long the investigation might take.

The Association of Zoos and Aquariums, an accrediting agency, also announced that it was investigating the Harambe episode. "We'll of course be taking a closer look at that working with Cincinnati to figure out what happened and make sure we can firm that up so it doesn't happen again," said to Rob Vernon, spokesman for the AZA.

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The U.S. Department of Agriculture, which inspects the zoo annually, said it will determine whether the incident happened because the zoo was not in compliance with the Animal Welfare Act , according to Public Affairs Specialist Tanya Espinosa.

If not, that would warrant a formal investigation, she said.

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"There is no time frame for looking into an incident or determining whether to open an investigation," Espinosa said. "We want to ensure that we are thorough."

CNN independently reviewed USDA records for the last three years, which is all that is maintained by the agency, and found nine findings where the zoo was out of compliance although none involved the gorilla exhibit.

Two involving veterinary care were directly tied to the health or wellness of the animals, and seven dealt with other issues; all were resolved, according to USDA reports.

Animal rights groups demands feds investigate

An animal rights group announced Tuesday that it had requested an investigation by the USDA. The letter from Michael A. Budkie , executive director of Stop Animal Exploitation Now, alleges the Harambe tragedy occurred because the zoo, "maintained an enclosure that violated the Animal Welfare Act," according to the letter obtained by CNN. It does not explain how the zoo violated the act.

The letter from the animal rights group cites what it says are Animal Welfare Act violations and includes copies of USDA inspection reports from March 2016 and November 2014, which CNN also located independently in the USDA database.

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The March 2016 report documented an incident in which two polar bears got into a service hallway that was to be accessible only to zookeepers. The dangerous animal response team was able to quickly secure the area and use tranquillizer darts to subdue the bears.

Separately, zoo director Thane Maynard noted a zookeeper lost her arm in a 1990 incident but didn't go into further detail.

The November 6, 2014, report cites a door to the Eastern black and white colobus monkey outdoor enclosure had multiple wooden boards in disrepair. The same report also detailed deterioration in part of the Przewalski's horse enclosure.

Child's mom at center of controversy

Meanwhile the child's mother, who works at a child care center for toddlers and preschoolers in Cincinnati, has been the target of much public anger after zoo officials felt forced to shoot 17-year-old Harambe, an endangered western lowland silverback, to protect her son.

"This beautiful gorilla lost his life because the boy's parents did not keep a closer watch on the child," the petition states.

Witnesses saw a boy in danger

Witnesses interviewed by CNN and its affiliates contended officials had little choice because it appeared the clamoring crowd was agitating the great ape, putting the boy in greater danger, even though it initially appeared Harambe was trying to protect the child.

One witness, Bruce Davis, told CNN affiliate WCPO in Cincinnati that he saw the ape toss the boy "10 feet in the air, and I saw him land on his back. It was a mess."

The tragedy happened after the boy told his mother he was going to get into the moat, and the mother admonished him to behave before being distracted by other children with her, Kimberly Ann Perkins O'Connor told CNN.

"The little boy himself had already been talking about wanting to go in, go in, get in the water and his mother is like, 'No you're not, no you're not,' " O'Connor said. "Her attention was drawn away for seconds, maybe a minute, and then he was up and in before you knew it."

The zoo announced that it had performed a necropsy on Harambe. One of their research doctors was able to extract and freeze Harambe's genetic material but no other details or plans for Harambe's remains were immediately available, said the zoo's communications director, Michelle Curley.

CORRECTION: An earlier version of this article incorrectly described an incident when a Cincinnati zookeeper lost her arm. That incident occurred in 1990.