An animal shelter in Bristow, Oklahoma — a small town southwest of Tulsa — is under fire for taking dogs to the back of the water treatment plant and shooting them. Witnesses claim the shelter has shot and killed at least three dogs in the past week alone.

“It’s not humane, period,” local activist Beth Roberts told The Daily Beast. “The way he’s dragging them over, putting them in the hole first, then shooting them.”

Activists are petitioning Bristow mayor Leonard Washington to stop the shootings, but the mayor is defending the practice, which by a loophole is fully legal.

“This is something that’s been a practice for 40 years,” he told The Daily Beast. “I don’t know why it’s a controversy … why such outrage now?”

While Oklahoma law requires animals to be euthanized “humanely,” it fails to define what “humane” is, leaving the shelter with the power to decide on its own.

The shelter reportedly shoots the animals because it’s cheaper than other methods of euthanasia.

“Of course, you’re going to have costs when you take it to the vet,” said Washington. “If you got 20 dogs you’re going to put down in X amount of months, you’re going to incur a lot of costs. It’s a matter of how you want to deal with it.”

Pit bulls are allegedly killed much faster than other dogs, allowing them just two days to be adopted before they’re euthaized.

Some Bristow residents also claim that the shelter has turned down their requests to volunteer, or even to donate food and other supplies.