CARTER COUNTY, Tenn. -

We're told a woman is recovering from numerous puncture wounds and bites all over her body after being attacked by her dog.

Richard Moore watched the attack happen from across the parking lot. He told us he didn't know his neighbor at 109 Oscar Banks Road in Johnson City, until around midnight on Sunday morning. "We heard a woman screaming, 'Help me, help me,'" he said.

Moore and his girlfriend looked outside and saw what police described as a 100-pound pit bull attacking a woman. "The dog was attacking the girl on top of the steps," said Moore.

He told us his girlfriend tried to distract the dog while he called 911.

We're told it took police four minutes to get to the scene. Moore said by the time they arrived, the victim and the dog had gone down two flights of stairs from a landing to the grass in front of the apartment building. Authorities told us the attack may have started in the woman's apartment.

The Carter County Sheriff's Office told us a deputy tried to draw the dog away from the victim and it charged at him instead. "He was able to draw his weapon and shoot and kill the dog to eliminate any further attacks," said Captain Jeff Markland.

"They shot [the dog] like three times. They had to," said Moore.   

We're told the 21-year-old victim was taken to the Johnson City Medical Center. "It was my understanding she wasn't really able to move at that point," said Markland.

Markland told us she had an emergency surgery. He told News 5 that the victim's wounds were so severe a deputy on scene had to drive the ambulance so both crew members could attend to the victim.

Markland said they don't know what caused the attack. "She had owned the dog for approximately 18 months, and had never had any problems with it prior to this whatsoever," he said.

He told us they will continue to investigate once the victim has recovered.

We checked with Carter County Sheriff Chris Mathes on Sunday evening and learned the victim is in fair condition.

We're told the dog was a year and a half old.