A tenant moved in and now says that the house is haunted. She wants to vacate. What is the best way to address the issue?

Inform her that she may be in breach of the lease if she vacates. Tell her that the landlord may exercise his default remedies under the lease. (The landlord must employ reasonable measures to mitigate any loss.) You might try to determine why she believes the house is haunted and see if there is a reasonable explanation for any mysterious circumstances. Also, ask the tenant to provide written explanations and requests for your records