Who Legally Can Collect Money

My husband bought a horse from a guy at work. After only 1 of the 5 payments being made the guy was arrested and we are not sure which jail/prison he is sitting in. His wife/girlfriend, we don't know which, is now coming around for the remainder of the money. We don't not feel comfortable giving her the money, when we don't know if she is the wife or girlfriend and since the horse was the guys and the deal was made only with him. She is now sending ''people'', not good, looking for my husband. Do we have to give her the money if she is the wife, and if she is the girlfriend does she have any legal rights to this money? Please help quick!!