Is Lee County Animal Services Responsible for warning me that dog can become aggressive due to breed?

In 2007 I adopted a dog from Lee County Animal Services, they gave me the dog as a male, she was a female, as verified by a vet to whom I took the dog after adopting. I went back to them for them to correct the gender of the dog. They listed the dog as Lab mix, but the dog is clearly a catahoula leopard mix. THey failed to tell me the dog of this breed has one unique development, when reach old age: she becomes highly aggressive. She target all other dogs we have many times, the stress and fear was high here at home for the last year till two weeks ago, when we euthanize her. Vet who oversaw the euthanize told us this is known and should have been disclosed to us before we decided to adopt her. This seems to be negligence from Lee County Animal Services. I need to know if you can counsel us on this matter and what can happen.