The dog was behind a fence in the family's front yard, attorneys say the family's civil rights were violated.
The incident happened in January when officers responded to a 9-1-1 call of two dogs fighting in front of the home.
In the end, one officer shot and killed one of the dogs. The family says the use of force wasn't necessary, and it violated their fourth amendment that prohibits unreasonable search and seizure.
3-year-old Simone was shot and killed inside her fenced enclosure at her family's home. Officer David Pilkington tried to subdue the dog that was fighting with another dog on the property when he ended up shooting her.
"It's not okay for anybody, let alone police officers, to come onto our property and take our property, in other terms kill our dogs," said John Torgenson.
The attorney for the owner says the family's fourth amendment rights were violated, and they're seeking $300,000 in damages. During the investigation, attorneys say they learned this wasn't the first time the officer opened fire on a dog.
"Completely unacceptable, he has shot three dogs in the last eight months, including this family's dog. That was very concerning for me to see two of those dogs were enclosed," said Torgenson.
During Pilkington's interview with the professional standards investigators he says he did not realize the dog was locked behind a fence until after the fact. He says he was trying to stop a vicious dog from getting loose.
"I took one shot, shot the dog somewhere in the back of the head, it dropped immediately... and then I stepped back to look and I realized oh this thing is contained, and then I kind of had an oh (expletive) moment, I realized this dog probably wasn't going to be able to get out of that area," said Pilkington.
Torgenson believes the officer's words infer he made the wrong decision.
"Acknowledging we think that he made a mistake, a mistake that cannot happen and should not happen," said Torgenson.
An internal investigation was completed, the details of that report will be released on Wednesday.