Well, there is an update, and not a good one, I'm afraid... I talked to the other dog's owner. She was extremely kind and sympathetic, but her vet did find wounds on her dog's neck and chest. Apparently, they were on the other side of the street (not even walking by our fence) which is where I found everyone. I have absolutely no reason to believe that she is being dishonest or has an agenda against my guy. Her dog is a mixed breed adopted from a local shelter. Yesterday, I had him on a lead in the yard while I was watering plants. Another dog came by and he charged the fence so hard that he pulled me down. He got to the top of the fence, but not over (I managed to hold on to the leash). I am worried for him... I have absolutely no idea what to do. He completely ignores me when he starts to chase/track, and now when there is a 'foreign' dog. I think his prey drve is manifesting itself into this aggression toward other dogs.