My question involves an injury that occurred in the state of: Maryland

My dog was killed in my neighbors yard. My kids play with my neighbors dogs all the time. We had no idea that the one dog was ultra aggressive. Without me knowing and in my children's innocence they grabbed our family dog and stepped just over our property line onto theirs...I believe (see more below). The neighbors one dog came over and was licking my dog. My dog was lying down enjoying herself. Out of no where the other dog that my neighbor owns darted over and mauled my dog. I heard the scream, saw it quick and so did the neighbor and we pulled the dog away. However, it was too late, I believe my dogs neck was broken in the first bite. My dog is 8lbs and the other dog looks to be a mix breed of some sort and the size of a boxer.

I don't know what I'm asking here, I just don't know what I should do next. I had no idea this dog would be so aggressive to kill and especially since my dog was just lying there without any aggression. She didn't even see him coming. I have the entire event on camera from the cameras around my house, but it's at a distance. I also question one thing, I remember my neighbor telling me that they do not put the electric fence collar on their dogs because they know where the line is and just won't cross it. I question whether my dog was truly over the line.

My dogs never cross over onto their property so we've never had an incident before. My children took our dog closer.

I guess I'm just wondering what do I do from here. Should I report it and why? If I don't want to go legal should I still report it? I feel if you have an aggressive dog is an electric fence enough? Shouldn't you tell your neighbors about his aggression? Shouldn't you say something especially when you see we have small dogs and small children?

Maybe I'm just upset.....