Why can the city take my dog with no proof

Today a guy was walking by my business and my dog got loose somehow and started barking at some guy. The guy started yelling for me to get my dog I ran outside and my dog was far from the guy. I called my dog and he came. I put him in his crate and the guy said your dog scratched me and asked for a bandaid. The guy left and a few hours later a city of Dallas Animal control came and said he needed to take my dog because the got a call that my dog bit someone. I told him I wasnt going to release my dog cops got there and said that I would go to jail if I didn't and they would still take the dog. I asked them for proof and they said they didn't need to provide proof and that they needed to Quarntine my dog. I had proof of his rabies shots and everything. My dog has never bit anyone and he goes to the vet regularly and does well there. What can I do? There should be a law for the victim accusing my dog to show proof. This means if I don't like u and I know u have a dog I can call the city?

The one law you did break was the City's leash law. The dog was unrestrained and off your property. They can confiscate your dog for that purpose. Also, if you didn't have current dog license, they can also confiscate the dog.

The guy is lying and there will likely be some process for determining if your dog is a vicious dog, such as a hearing. You may want to ask Animal Control when the quarantine period is over and what will happen after that. Based on what your hear, you may want to consult with a lawyer.