ELGIN, Ill. (CBS) — A dog turned on its owners Thursday evening, attacking the man and woman in northwest suburban Elgin.

The owners were seriously hurt—and police had to take down the animal to keep everyone safe.

Just before 5 p.m., neighbors in the 900 block of High Street in Elgin heard screams nearby. They could instantly tell they were hearing cries of distress.

“I thought to myself, what the heck is going on?” said neighbor Roger Foehringer.

The neighbors stepped outside to find the dog attacking its owners. They called 911, and Elgin police and emergency crews quickly filled the quiet neighborhood.

The dog turned its owners for reasons unknown.

“A couple was walking their dog, it got angry at another dog, and then it attacked the owner—attacked both of the owners,” said neighbor Mark Freshour, “and it finally grabbed the woman’s arm, and it got both of her arms—tore it down to the bone.”

Witnesses said once the dog locked down on the woman, the man tried his best to get her free. He was even injured in the attempt.

By the time officers arrived, Elgin police said the responding officer had no choice put to pull out his weapon.

“The officer pulled the gun and shot the dog,” said Freshour. “It was no way to get that dog to turn loose. It was clamped on so hard, they were trying for five mins to get the dog off.”

Killing the dog was the only way police and witnesses say the dog let go. Once free, it turned out the woman’s injuries were so severe that the officer started a tourniquet to stop the woman from bleeding.

“She was bleeding in so many places,” said Freshour. “It was awful.”

Freshour said the actions of the officer—by shooting the dog, but also tending immediately to the woman’s injuries—were nothing short of heroic.

“I akready told them I appreciated their service, and how fast they responded,” Freshour said.

Police said the two victims will survive. They were hospitalized ins serious condition late Thursday.