Atop Marion County's landfill Friday, thousands of birds circled over trucks spreading fresh loads of garbage. Among those birds, a handful of bald eagles were spotted.

It was earlier this week county solid waste workers found two bald eagles lying on the side of the landfill. They were immediately treated by the Animis Foundation.

Animal caretakers with Animis say the eagles were very lethargic and needed oxygen and fluids to flush out their systems. One of the eagles later died, the other is recovering. Tests are still being done at the Audubon's Birds of Prey Center in Maitland where the animals were taken. But caretakers at Animis say they’ve done tests of their own before, and always come back with the same answer.

“They showed symptoms of pentobarbital poisoning which we have seen previously with other eagles we have picked up from the same place," Animis caretaker Danielle Ball said.

That poison is what’s given to animals when they are euthanized.

At the foot of the landfill sits the Marion County Animal Shelter.

“The belief is the animals that are being brought to the landfill are not being given the proper burials or handled in the right way, which is leading to the eagles having access to them,” fellow Animis caretaker Mark Quadrozzi said.

U.S. Fish and Wildlife Services and Florida Fish and Wildlife investigators were at the landfill Friday trying to see if that's the case.

Solid Waste Director Mike Sims said whenever they are notified they are getting a delivery of animals, they dig a hole at least 3 feet down into the landfill, exceeding state standards of 2 feet.

Sims said the animals are then quickly buried by other trash in accordance with state statute in part to protect birds of prey.

“We’re as much concerned about this and we want to get to the bottom of this if it is our facility. So we are going to cooperate with any agency that is going to come and investigate,” said Sims.

The investigation was prompted by an outpouring on social media after the Animis Foundation publicized their beliefs about the cause of the eagles' illness.

“I feel like everybody working together we can solve this problem and make Marion County a safe place for our national bird,” Quadrozzi said.

Investigators say any findings could be turned over to the U.S. Department of Justice.

Marion County Animal Services points out the animals they euthanize account for less than a third of the animals that go in the landfill each year.

Solid Waste said its also investigating whether businesses and residents are properly notifying landfill operators they are bringing in animals to be buried.