Check with your county and city.
I have not killed a dog but came very close one time.
Dog was attacking neighbors pig.
Neighbor was not home during this event.
Was not on my property so used a bat to stop the attack.
Got bit during all this.
Pig had to be put down and dog sent to vet.
Asked neighbor if he gives me permission to use a firearm on his property.
He put it in writing and the dog owner has been warned.
Dog owner was fined by animal control and had to pay for pet pig.
Having your sisters dog killed and her face ripped off is not acceptable.
This is not your sisters fault.
You have to get animal control involved.
Not sure if anyone has seen what a pack of "nice family" dogs can become.
Just like people once in a group they feed off each other.
The hunt and taste of blood will change them forever.
I blame the owner but unfortunately the dog pays the ultimate price.
Does not have to be attacking only "worrying"