Attorney Jeffrey P. Coleman gives some examples of the type of investigation required when challenging a will in a will contest case.
The evidence that you will need to present in a will contest will largely be determined by the theory that you’re using an attack on the will. If you’re saying there’s undue influence, you’re going to need to find out a lot about the person that procured or pushed that will through. If on the other hand if you’re trying to attack the formalities of the signing of the will, you might want to find out that one of those witnesses that was supposedly executing and witnessing the will was on vacation in Las Vegas at the time. It’s important for you to do your investigation and to have an attorney to help you do that in a will contest.