Use the "find a lawyer" tool on AVVO to find an Animal Law attorney to help you. Your situation is difficult. Normally, you are strictly liable for what your dog does. However, it should be argued in your defense that these dogs attacked your dog. Since your dog killed this other dog, it is vulnerable to confiscation and euthanization if the case is not properly made about your dog being attacked first.
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"...my dog saw him and rushed toward the fence and before I could do anything he went threw the bar ..."
Which is to say, your neighbors had their dogs in THEIR yard, and YOUR dog entered THEIR yard and killed one of their dogs. That is hardly the neighbor's fault.
Use the Avvo find-a-lawyer function or contact the OH and Cleveland bar associations for referrals.
The foregoing is for general information purposes and does not establish an attorney-client relationship.
You do need a lawyer - your dog was on their property and attacked their dogs, killing one. Even though you are generally not required to have your dog on leash in your own yard, you are required to have them under your direct control. In addition, if it was your fence you are under an obligation to keep it in good repair so the likelihood of a dog getting through is lessened.
If we do not have a signed fee agreement I am not your attorney and this is not legal advice.