I am interested in buying a house that is not on the market. I spoke with the neighbor and the previous owner is deceased (for about 2 years)

Although you could do this yourself, I would first recommend that you consider getting a realtor or experienced real estate attorney to help you through the process, especially if you have never done it before. As for the identity of the lender, you should be able to go to the online public records, or down to the courthouse/clerk, and search the property and obtain information identifying the current owner and lender.  If the prior owner is deceased It is highly likely that you will need to be involved somehow in a probate administration of the estate, if one has been commenced. Getting access to the probate case records is more difficult, and is another reason to engage an experienced real estate attorney. This is specific to Florida law and does not constitute legal advice as the facts presented are anonymous and incomplete. This is intended for general education only and does not create an attorney-client relationship. This should not be relied on and you must seek your own attorney client relationship.