IRON RIDGE, Wis. -- A friendly get-together between two families in Wisconsin turned tragic Wednesday when a 4-year-old girl was attacked and killed by the pet dog.

"Just a terrible event," Dodge County Sheriff Todd Nehls said.

The girl and her family had visited the home, and the dog, many times before, he said.

When the male boxer attacked, he and the girl were alone, so no one knows what set off the animal.

"You'll never be able to answer why the dog reacted or did what he did," Nehls said.

A neighbor passing by saw the attack from the road and started pounding on the family's front door, telling them to call 911.

For nine minutes, a dispatcher gave CPR instructions over the phone. Then various emergency personnel tried for more than an hour to save the little girl's life.

She was later pronounced dead at Beaver Dam Community Hospital. The dog has since been euthanized.

Across the street, Shirley Blecher was praying for the family who lost their little girl and the family whose dog attacked.

"That's got to be horrific," she said. "I wouldn't want to be in either one of their positions."

The Sheriff's Department is investigating the death, but doesn't expect to file any criminal charges.