My Mali, Dutch, is a very well behaved dog with people especially with myself. He is amazing with kids and listens when spoken too. We believe he is about a year old, we were not provided with any sort of certification. I have had him for almost a week but he is very affectionate towards me. I walk him take him to the park and give it hours to run on its own at the park. He just gets home and lies down tiredly. His first owner was a cop who was a K-9 Training Officer. I believe he must have failed some kind of exam because he was taken to a shelter. His second owner was someone who wasn't financially stable and had a pitbull. The pitbull was extremely aggressive and constantly aggravated Dutch. So he offered me Dutch because of it. Today I took it to the vet and he was walking very well with me. Mildly distracted with grass, cars, etc. Just the usual. But when he sees a dog he gets very aggressive. When I took him inside the office he was okay with the smaller dogs. He just tries smell them and whatnot but very anxiously. When he saw a larger dog or just some aggressive looking dog he attempts to attack, growls, and barks viciously. Everyone there were saying what a bad and aggressive dog. It really made me angry because I know he is not that way. I had to leave because of his behavior. I believe that behavior is due to the pitbull from his previous owner and not from himself. Maybe he is just afraid and does it out of fear. I really need to get this fixed and learn how to control the action. I just wont feel safe taking him anywhere anymore even though I have too. Please tell me what I can do I need a legit answer and solution. I love him very mush and would hate him to get hurt.