Neighbors witnessed a man strangling his dog, then beating it with a shovel, on his Levittown home's front lawn on Friday afternoon, Nassau County police say. The dog, an 11-year-old border collie mix named Bella, was euthanized and Michael Gallagher, 56, was arrested later that evening.

A neighbor told WABC 7, "My neighbor across the street called me, screaming that she heard the dog being killed." When she looked outside, she saw Gallagher on the lawn with Bella. "All of sudden, he comes out with this long zip tie," she said. "And he's putting it around the dog's neck. The dog is in the bag," she recalled.

"I screamed at him to stop and said, 'What are you doing? What are you doing?'" she said. "And he said the dog was sick, and he wanted to put it out of its misery. And I called him a couple of things."

The neighbor opened the bag, cut the zip ties and saw a bad cut on the dog's head.

A neighbor said

, "You couldn’t even see the tie around its neck because it was that embedded." Gallagher also allegedly slammed a shovel into the dog's head.

He left the neighborhood and neighbors called his family about the incident. His daughter, Kerry Gallagher, said that her father had quit drinking six months ago, but started again when one of their other dogs died early in the month, "I think he either just blacked out or something snapped in his head. He’s never been violent with the dogs ever before. He loves animals."

Gallagher, who works as a plumber for the NYC schools, was arrested at a 7-Eleven at 10:30 p.m. He apparently told detectives that he didn't remember the attack. He has been charged with aggravated cruelty to animals and torturing or injuring animals is being held on $300,000 bond or $150,000 cash, according to Newsday.

Bella, who had been adopted by the family 11 years ago, was euthanized. Gary Rogers of the Nassau County SPCA said, "The vet determined that the wounds were going to be fatal, and to put the animal out of its suffering."

Kerry Gallagher said to the Post, "I was able to say goodbye, at least. She was a good dog, she did not deserve that. … Something snapped in my dad’s head."