CINCINNATI (AP) — Police said Tuesday they are investigating the parents of the 3-year-old boy who fell into a gorilla enclosure at the Cincinnati Zoo and had to be rescued by a team that shot the 400-pound animal to death.

Authorities said the investigation will look at the parents’ actions leading up to the incident – not the operation of the zoo, which is overseen by the U.S. Department of Agriculture. Police will then confer with prosecutors over whether charges should be filed, Hamilton County Prosecutor Joe Deters said.

The incident has triggered a furor online, with some saying the boy’s mother should be charged with child endangering, while others want the zoo held responsible for the animal’s death.

Separately, USDA said it will investigate Saturday’s incident for any violations of the Animal Welfare Act.

Zoo authorities said the unidentified boy climbed over a 3-foot-high railing, walked through bushes and plunged about 15 feet into a shallow moat. The zoo’s dangerous-animal response team killed the gorilla as it dragged the boy through the water, authorities said. The boy had only minor scrapes on his head and knee, according to police.

Ohio State University criminal law professor Ric Simmons said he doubts a charge of child endangering could be proved in this instance, since the offense typically involves leaving a youngster unattended for an extended time, not a case of a child momentarily wandering off.

“The mother was standing next to a zoo exhibit and lost track of her child for perhaps a minute or so,” Simons said in an email. “That has happened to almost every parent in the world in a public place.”

The boy’s family said he is “doing just fine” at home, and it had no further comment.

A federal inspection by USDA less than two months ago found no problems with the Gorilla World exhibit, but earlier zoo inspections detailed an incident in March in which polar bears escaped through an open den door into a behind-the-scenes hallway. No one was hurt, but an inspector warned that the public could have been “at great risk for injury, harm or death.”

Zoo director Thane Maynard said that using tranquilizers on the gorilla would not have knocked the animal out right away, leaving the boy in danger. Maynard said 17-year-old Harambe was agitated by the commotion from the crowd and was extremely powerful, capable of crushing a coconut in one hand.

He said the zoo remains safe for its 1.6 million annual visitors, but a review is underway to determine whether any improvements can be made.

Donald Trump weighed in Tuesday, saying the zoo had little choice but to kill the gorilla. Trump said it was “a very tough call,” but the child’s life was at stake.

The executive director of a Cincinnati-based animal rights organization is calling on the USDA to fine the zoo.

“The barrier obviously isn’t sufficient to keep the public out,” said Michael Budkie of Stop Animal Exploitation NOW. “Otherwise, Harambe wouldn’t be dead.”

Jack Hanna, host of “Jack Hanna’s Into the Wild,” said the zoo made the right call by shooting the gorilla, telling WBNS-TV: “I’ll bet my life on this, that child would not be here today.”

In an interview with Boston TV station WFXT, conservationist and television host Jeff Corwin suggested that the boy’s family should shoulder some of the blame, saying: “Zoos aren’t your baby sitter.”