About two years ago I was in a similar situation, dirt bag neighbor had to bulldogs that would not stay in the yard, first time they came over I fired a warning shot and they ran off. I told the neighbor if they did it again I would put them down, I love dogs but have two small children that wouldn't stand a chance against an attack. About a month later the dogs attacked as I was bringing up the garbage cans. I put one down as it lunged for me and the second one right after.
Were there any legal consequences for that? I'm assuming you at least had to do a police report