Well, first of all, the divorcee certainly must have received a copy of something that states that they are now divorced, rather than just taking someone's word for it. I for one, if I wanted a quickee divorce, I certainly would want the one I was divorcing to knwo that it had at least happened, otherwise it's as good as a woman saying, "I'm on the pill."
If she (or he, but probably not) did receive these forms, the will be a date or at least a stamp showing exactly where they were filed. Follow the paper trail. If there were no papers filed, and the divorcee never did formally consent, chances are pretty good that she is still just as married as their wedding day. My advice, go down to your local courthouse and file for yourself, because if you didn't sign in the first place, and you want a divorce, go ahead and do it now and put down everything that you want!