Believe it or not, depending on what state you are selling a home in, you may have to disclose to a buyer if you believe your house is haunted, or there has been any paranormal activity!
The traditional rules regarding the law on home sales were known as "caveat emptor", or "let the buyer beware". This law stated that sellers were not required to disclose any history or weird happenings about the home they were trying to sell. But there are some states that have made changes to this rule, requiring the disclosure of certain information – such as information about murder, suicide, or what’s known as a haunted house.
For example, Massachusetts and California both have specific laws about disclosure when it comes to hauntings, or any negative information associated with the home. Here is a link on specific state laws when it comes to disclosure: http://www.nolo.com/legal-encyclopedia/required-disclosures-selling-real-estate-30027.html.
Just remember, when you are asked a direct question, you MUST answer truthfully, even under caveat emptor. Otherwise, it is considered misleading and you could be sued by the new owners!