Updated: June 2, 2016 11:44 AM ET | Originally published: May 30, 2016 4:32 PM EDT

Dozens of people gathered at a vigil on Monday for the gorilla killed by Cincinnati Zoo officials Saturday to protect a three-year-old boy who fell into the animal’s enclosure.

The gorilla, named Harambe, was shot and killed by the zoo’s Dangerous Animal Response Team after grabbing and dragging the toddler through a shallow moat.

“People can shout at the parents and people can shout at the zoo,” said Anthony Seta, an animal rights activist in Cincinnati, the AP reported. “The fact is that a gorilla that just celebrated his birthday has been killed.”

In the days since the gorilla’s death, animal rights activists have criticized the toddler’s mother for not watching him closely enough and the zoo for not using fencing that could have prevented the boy from falling inside. The incident also prompted several celebrities to speak out and criticize how the situation was handled.

“We are heartbroken about losing Harambe, but a child’s life was in danger and a quick decision had to be made by our Dangerous Animal Response Team,” said Zoo Director Thane Maynard in a statement on Sunday.

Those mourning the death of Harambe gathered at a vigil Monday afternoon, the Guardian reported. A Facebook page for the vigil emphasized that the event was a tribute to the gorilla, not a protest of the zoo. Visitors had also been leaving flowers and cards at a makeshift memorial near a statue outside the zoo’s Gorilla World, which was temporarily closed on Monday, the Cincinnati Enquirer reported.

Read more: Caretaker of Slain Cincinnati Zoo Gorilla Devastated: ‘These Are Like Your Children’

“Yet again, captivity has taken an animal’s life,” People for the Ethical Treatment of Animals said in a statement from its primatologist Julia Gallucci, local station WCPO reported. “The gorilla enclosure should have been surrounded by a secondary barrier between the humans and the animals to prevent exactly this type of incident.”

In a statement released Sunday, the family of the toddler—who has not been officially identified—thanked zoo employees for their quick action.

“We know that this was a very difficult decision for them, and that they are grieving the loss of their gorilla,” the statement said.

More Must-Reads From TIME

Write to Katie Reilly at Katie.Reilly@time.com.

You May Also Like