As a general rule, security deposits need to be returned only if the tenant leaves the apartment in the same shape as when it was rented. Assuming you were not at fault in causing the fire, it sounds like your tenant caused more damage than what would be considered normal wear and tear. You should send written notice to the tenant explaining why the deposit is not being returned. Be sure to include an itemized list of what was damaged and the cost to fix it. Before you do anything, though, you should read your lease agreement carefully to see what it says about damages to the apartment.
Leases often contain special provisions dealing with what happens when there is fire damage.
Q. I own a house along with my 12 siblings. The house probably isn't worth much. A. Going to court to seek a judicial partition of the house means hiring a lawyer and paying for the filing fees and other miscellaneous costs. Lawyers normally charge by the hour in this type of matter, and the total number of hours will depend entirely on the level of opposition raised by your siblings. Most lawyers will require a retainer equal to a portion of the expected legal fees as well as all of the filing fees and other costs.