A Daytona Beach couple attacked by their pit bull on Sunday had to kill the dog in order to save their lives, their son said to a dispatcher in a 9-1-1 call.

Michelle Scott, 54, stabbed the 75 to 80 pound pit bull to get the animal off her husband, Scott Stevens, 57, but not before the dog bit off part of his finger, police said.

Both Scott and Michelle Stevens were taken to Halifax Health Medical Center to be treated for their injuries, investigators said.

"I'm calling for my mother and father. They've been mauled by their pet pit bull," Marshal Wallot told a dispatcher. "They've been mauled. The end of my dad's finger's been bitten off."

Wallot said in an interview Monday that his mother had no choice but to kill the beloved pet because she was defending his father's life.

"They tried to restrain the dog as best as they could," Wallot said. "But it kept coming after them, the dog was relentless and fearing that it would go for my father's throat, my mother had no choice but to dispatch the dog."

The couple have their own dog at their Pelican Bay home but had been watching the larger black and white pit bull for a friend for a year, according to a police report.

The couple were feeding their dog around 7:23 p.m. when it attacked their dog.

Wallot said the pit bull, Tyson, was playing with a toy in the living room when their Labrador mix tried to take the toy away, causing the dogs to fight.

Wallot's father tried to separate the dogs but the pit bull turned on his father and grabbed his arm. His mother then tried to defend his father and the dog turned on her, Wallot said.

Police said, fearing for her husband's life, Michelle Stevens grabbed a kitchen knife and stabbed the pit bull several times but the dog continued its attack. Her husband suffered several more injuries, including losing part of his finger, before the dog collapsed, a report states.

The tip of Scott Stevens' right index finger was removed by the dog's teeth, officers wrote in their report.

Wallot said it was hard on his parents having to kill Tyson, because he was a good dog, but his mother had to act in self-defense. The incident was a "freak accident that unfortunately came to a life-or-death situation," because Tyson had never acted out before, Wallot said.

"They did what they had to do to survive," Wallot said. "The dog was stabbed so my father could live."

The pit bull was found dead at the scene of the attack, police said.

In the 9-1-1 call Wallot said: "They had to kill it in order to survive."

Scott Stevens suffered multiple puncture wounds to his right forearm and right leg and Michelle Stevens also suffered puncture wounds to her right forearm and left leg and possibly a broken right wrist, police said.

Wallot said his father is out of the hospital and at home recovering in a stable condition and his mother is still at the hospital being treated.

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