I am sooo sorry! Oh, how miserable! I worry about the same thing. I have close neighbors all around me that have either hunting dogs (bird dogs) and 1 neighbor with 2 Chihuahua/terriers. The 2 little ones get chased out of the yard regularly. Fencing goes below the ground, but I still worry.
You have a picture of the guilty dog. Shoot it if it comes back. I would think you have legal grounds for it.
A neighbor a couple blocks away had a different neighbors dog get in and killed about $200 worth of birds. They didn't press charges (small community), but there was the strict understanding if it happened again the dog would be put down. I'm not so sure I could have been so forgiving.
Were the dogs rounded up and brought into the pound?