I had something similar happen with me a few years ago. I was walking my German Shepherd who was an absolute monster of a shepherd weighing an easy 120lbs at any given time. I'm walking him near this park by my house when I see the guy I always dread to see. Everyone has that one person they hate to see and this was him for me. By the way my German shepherd was a professionally trained and previously retired police k9 dog who retired with my step dad from the force. So this guy is piss drunk and walking his rottweiller/lab and an older chocolate lab/pit bull. Both dogs are very dog aggressive and this drunk asshole refused to use a leash beside the fact that it is posted everywhere to use a leash. So anyways I see this guy approaching from a distance with his two mutts charging at me and my shepherd already barking. They were at least 250 feet from me and I quickly unhooked my dogs leash and decided to just let him do his worst to these dogs rather than have them bite him while on a leash. So before I know it they are both close and growling and now slowly approaching my dog and I guess sizing him up. Both these dogs together still probably didn't weigh what my shepherd did for a size reference. The lab/pit was a pretty old and beaten down looking dog and it was staying back behind the rottweiler mix. Within seconds I let go of my dogs collar and just let him go after these dogs who were circling us and about to bite him. My shepherd jumped at the rotti mix and grabbed it by the throat and shook it in his mouth holding it there while it whimpered hopelessly, the pit mix was still close by and it actually snapped at my dogs leg and must have bitten it quickly as he dropped the one dog he had by the neck and went after the other. Within a few seconds the other dog was within reaching distance from mine and still growling and barking at my dog who just barely let his larger friend live, he lunged at the pit and got a hold of his front leg and tore him open. This whole time I was checking on the dog I thought mine had just killed to see if it was still alive and this all happened in a matter of seconds. Both dogs were bleeding like crazy and my dog had left the lab/rotti with an ounce of life left on the floor of a field while the other had his leg bleeding like crazy. My shepherd had a bite mark on his back leg from the sneak attack by the pit/lab but that was all I found on him. Those dogs never came anywhere near him again after that so I guess they learned their lessons. The drunk bastard came over to me screaming and yelling threatening me and stuttering his sentences. I ended up calling the cops and explaining everything that happened and it was a huge mess but he ended up being liable and getting tickets for having his dogs off leashes in public. Fuck shitty dog owners and I really miss that beast of a shepherd he was a great dog