DETROIT -- A dog owner has plead guilty to what Humane Society employees said was the worst case of torture they have ever seen.

Investigators said John Delmar Fladger, 44, of Detroit, poured gasoline over his dog and set him on fire last month.

One witness said the owner first tried to burn the dog inside a convenience store.

"Yes, inside the store. He was pouring gas," said Evon Yusef, who witnessed the attack. "There was gas all over the place. Customers were scared. They were backing away from him."

Another witness told investigators from the Michigan Humane Society that the owner later seemed to be showing off in front of a group of children.

"He was walking down the street, spilling gas at the dog. He was trying to light the dog at the same time he was walking," the witness said.

Natatia Nix of the Michigan Humane Society called it one of the worst cases she has ever been a part of.

"The (Humane Society) staff sees everything that comes in. We see the hit-by-a-car dogs, the gunshot dogs, the neglected dogs -- every type of abuse," Nix said. "But this ... We were just looking around the room. We were in there with the dog -- each of us were crying."

Nix said the dog, a shepherd mixture, was so badly burned that treatments did not help, so the animal had to be euthanized.

During the investigation, the owner originally denied hurting the dog, but pleaded guilty last week to animal torture and the killing of an animal.

The owner is scheduled to be sentenced later this month. He faces up to four years in prison.