Here is a site that covers the US of animal abusers. It is not for the faint hearted. I had a good cry when I read all the suffering and needless pain that has gone on!
This group would appreciate any reports of abuse you discover. They will also research a case for a reasonable fee. They quote newspaper stories and follow-up results all over the U.S. They are a group of animal lovers who decided this was a needed service and are doing their best to keep comprehensive records, and need all the volunteers and aid they can get.